Need help with reverse light wiring - 1965 / 1966

[jeffmort]

I need help figuring out to make my reverse lights work.
My car is a 1965 Corsa but the transmission is from a 1966 with the reverse switch located in the side of the transmission (which I have learned is different than a 1965 style switch).
I do not have the reverse light "plug" that comes off of / is attached to the main body harness. When inspecting the main wiring harness, the reverse light wires that runs through the main harness was somehow "burned up/melted". The car is new to me so I don't know how this happened.
I don't want to replace my entire body harness simply to make the reverse lights work. If this is the only way to fix it, then I will choose to leave my reverse lights not working.
So... I currently have no wires coming off of my reverse light switch. I'm pretty sure I can figure out how to send a 20 gauge black/light green wire from the reverse light switch on the transmission back to the engine wiring harness and then on to to my reverse lights.
Unless I am missing something in my above plan, what I need help with is how to best run a wire from the reverse light switch "forward" to a proper power source - which I assume would be a power source that is "on" only when the ignition is on.
Thanks.
Jeff

[joelsplace]

If you don't want to replace the harness you should unwrap the old one and replace the burned wires. Often they have burned other wires they were touching so it will give you a chance to fix that damage also. Then you will have it wired like the factory and the next person that is in there will thank you.

[bbodie52]

» Tue Mar 09, 2021 5:00 pm

I'm a new Corvair owner as of this past weekend. Well I guess its my second Corvair - first one was a 1965 Monza that I purchased when I was in high school in 1983. I didn't know a thing about Corvairs then, other than my engine fell out one time while driving!
Now I know a lot more about cars and have had many 1960-70's Chevy's (multiple Camaros, Corvette, Nova, etc.). Now I am back to my high school Corvair with more general knowledge and interest but limited Corvair specific knowledge.
This car is in decent+ running condition: suspension and brakes are fresh - drives straight, brakes straight, interior is in good enough order, all gauges work. Needs paint and cosmetic work but body is generally good.
Motor seems to be well cared for - has Pertronix ignition, internal regulated alternator, turbo was recently serviced, heads were recently rebuilt, doesn't leak oil. Engine runs smooth and reliable.
Transmission/clutch may need some attention - grinding noise while downshifting into second gear, release bearing sounds a bit noisy and a bit of chatter when i start off from a stop.
While most of the parts are period correct for the car, they are not necessarily original to the car which is fine. 4-speed transmission and differential are from 1966+ car (as determined from the case numbers and the 6 bolt mounting set up).
Importantly, the engine block is RL block and the turbo serial # checks out. Heads are 110's that were recently upgraded/service by Ken Hand (Michigan).
My plans for the car is to learn more about it mechanically and address any issues and then turn to cosmetic issues (paint, etc.).
The car was previously owned by a "Corvair guy/Corsa Club guy" named Ray Chapelle out of Marysville, WA. Unfortunately, Ray passed away sometime last year. I just purchased it more or less from his "estate" or heirs so the car will kept in the Corvair community.
I am sure I will be frequenting this forum at first seeking help/advice and maybe ultimately contributing some day.
Thanks.
Jeff
Encinitas, CA (So Cal)

The backup light system for the manual transmission is a fairly simple circuit that should be easy to trace with a multimeter, perhaps by substitution
to verify each segment's functionality from the rear backup lights looking forward, through the engine compartment multiconnector, to the transmission switch, and forward to the power source. For example, if you separate the two halves of the engine compartment multiconnector and identify the backup light terminal within the connector, would applying 12 VDC there cause both rear backup lights to illuminate? Is electrical continuity good and verifiable from that connector back to the bulbs to cause them to illuminate? If that segment is confirmed, can the next segment to the transmission backup light switch also be confirmed? Can that switch be manually operated by hand to cause it to function and confirm electrical continuity to the rear lights? (If so, screwing it back into the transmission and confirming that the switch is mechanically activated/closed by shifting to REVERSE should also be easily verifiable. (I am not aware of any ball bearing between the transmission and the switch). If the switch and wiring is confirmed from the transmission back, the final segment going forward would be to confirm with a multimeter if the wiring harness is actually tapping into 12VDC (switched by the ignition switch to provide power only in the ON position of the ignition switch, I believe). This form of troubleshooting and fault isolation should lead you to the non-functioning segment(s), so any faulty portion can be corrected and you will end-up with a fully functional backup light system in your Corvair.

I have gathered multiple illustrations below, and several references (attached) to guide you and to help you visualize the backup light circuit, which is a fairly simple electrical circuit. The poser source originates at the fuse block, and routes to the heater fan switch. (Does your heater fan work? If it does than you know that portion of the circuit has power). From there a Dark Green wire taps off of the fan switch harness, routes through a 12-pin multi-connector behind the dashboard, and continues on via the tunnel under the car toward the transmission backup light switch. (That segment changes wire color to 20 B/LG (20 Gauge Black with Light Green stripe). You will have to do some investigating as to how far that wire goes from the multi-connector to the tunnel) Once the wiring leavds the transmission area, it continues through another large multi-connector in the engine compartment. It exits the engine compartment multi-connector as two wires, spliced at the connector. Each wire routes to one of the backup light sockets. Assuming that each lamp socket is properly grounded and contains a serviceable 1156 bulb, if you can get switched 12 VDC for the engine compartment multi-connector output to the backup lights, they should come on.

As discussed below, you do not have to make use of your transmission switch to control the circuit. Clark's Corvair Parts offers a substitute repair kit that makes use of the in-tunnel 3-speed transmission switching system that uses an external switch to control the backup lights (the 3-speed transmision had on integrated switch, but used a switch that linked directly to the transmission shifting tube). YOur job will tbe to locate the power source that travels formthe fuse block, passes through the heater fan switch harness, and continues via a multi-connector behind the instrument panel and down through the tunnel. YOu can choose to install a 3-speed switch or use the transmission switch, nd then make the connection to the engine compartment muli-connector. Once you recreate all of the needed wiring segments and a function switch, you should have backup lights.

I would be concerned about the apparent faulty synchros in the transmission that may be related to your described problem with "grinding noise while downshifting into second gear," and "release bearing sounds ... and a bit of chatter when i start off from a stop." You could be looking at a need for a clutch inspection and repair, and possibly a faulty or worn transmission. (If a previous owner happened to drain/refill the transaxle with GL-5 gear lube, instead of using GL-4, the chemical makeup of GL-5 lubricant can damage the "yellow metal" brass synchro gears inside the manual transmission. Excessive wear or damage to those gears could be a warning sign of a future need for a transmission replacement or overhaul, possibly caused by the use of an incorrect GL-5 gear lubricant.

Heads are 110's that were recently upgraded/service by Ken Hand (Michigan).

Were the "110hp" heads modified to work with the turbocharger? The right head would have to have a plumbing connection to drain oil from the turbo back onto the engine (into the rocker arm area). Also the compression ratio in 110hp heads is 9:1, while normal turbo heads are 8:1. The higher compression ratio might cause detonation issues when used in conjunction with the turbocharger. Check the cylinder head casting number to verify the heads used.






LEFT-CLICK THE IMAGE TO ENLARGE FOR BETTER VIEWING. CLICK A SECOND TIME FOR MAXIMUM ENLARGEMENT...

1965 Corvair Corsa Full Schematic

T1961-65 Corvair 4-Speed Transmission Backup Light Switch (PN C9725)he backup light switch sticking out of the bottom of the 4-speed transmission is simply supposed to provide that "short" between the positive voltage source and the other wire, which feeds the voltage onward to the backup lights when the switch in the transmission is closed (transmission shifted to REVERSE). Sometimes the switch goes bad, or it gets damaged because it sticks down and can be struck if the car is driven over an object that hits the switch. Use the ohmmeter in your multimeter to check the tw wires for electrical continuity when the transmission is shifted to REVERSE. There is also a nylon washer that seals the threaded end of the switch to the transmission. Occasionally more than one washer is left there, moving the switch too low so it fails to be closed when shifting to REVERSE.




This wire leads from the 4-Speed manual transmission Back-Up Lamp Switch. It should be connected to the wiring harness and turns on the backup lights when you shift the transmission to reverse. The wiring connector for this switch should be located in the underbody tunnel. According to the shop manual the 20 GA. wire color is B/LG (Black with Light-Green Stripe).


1961-65 Corvair 4-Speed Transmission Backup Light Switch
Clark's Corvair Parts Backup Light Switch
https://ssl.corvair.com/user-cgi/catalo ... N&page=84B

https://ssl.corvair.com/user-cgi/catalo ... w_page=84B

Part number C8379: 4 SPEED BACK UP SWITCH FIX-THEY LEAVE OLD SWITCH IN PLACE-THIS WORKS OFF SHIFT ROD

Weight: 1 lbs 0 oz
Catalog Page(s): 84B
Price: $ 44.30







=================================================================================================

More possibilities...

Backup switch repair new

http://corvaircenter.com/phorum/read.php?1,1116570

[gbullman]

If you don't want to replace the harness you should unwrap the old one and replace the burned wires. Often they have burned other wires they were touching so it will give you a chance to fix that damage also. Then you will have it wired like the factory and the next person that is in there will thank you.

I agree with Joel, you can't just leave melted wires without understanding the extent of the damage. I've repaired a couple of harnesses now that had limited melted wires. Also, the best you can try and figure out why they melted and correct the cause if you can. The good news is all pins are available from Clarks if you just want to replace wires, you can do a factory like job of it.

My backup lights on my 66 4 speed aren't working at the moment but I'm guessing I knocked a wire or connector loose when I did a bunch of work underneath this spring.

[jeffmort]

Thanks for the info.
When I did my initial inspection and found the unknown "melted" wire, I removed the melted wire and capped it off as well as conformed that all other wires were in tact and undamaged.
That said, I have now decided to replace the body wiring harness (I initially though this harness cost $400+ but I was looking at the fuse block harness. Body harness is around $125 so I will just buy a new one. Will also buy the reverse light Fix It kit from Clarks. Will see how I do with these new parts.

Other question I have as I am rewiring: there are two firewall grommet locations - I'll refer to them as the "low" grommet and the "high" grommet. I am trying to figure out which items go through which holes (fuel & fuel return, vacuum gauge hose, starter motor harness, main harness, battery cable).
I checked my assembly manual and didn't get a clear picture of how these lines should route.
Here is what I have come up with:
Low grommet: starter motor harness, battery cable
High grommet: body harness, fuel line, fuel return line, vacuum gauge.

Any pictures of correct set up would be great.

Thanks in advance.

[jeffmort]

Just got it back from paint and reinstalled all trim - getting there!

[jeffmort]

as far as my non-turbo, 110 cylinder heads go, they do I have an oil cooler line from turbo unit to right hand cylinder head (see pic), I am assuming that the head builder (Ken) was aware these heads were going to be used on a turbo?? Hopefully the heads were redone with turbo in mind??

[terribleted]

Thanks for the info.
When I did my initial inspection and found the unknown "melted" wire, I removed the melted wire and capped it off as well as conformed that all other wires were in tact and undamaged.
That said, I have now decided to replace the body wiring harness (I initially though this harness cost $400+ but I was looking at the fuse block harness. Body harness is around $125 so I will just buy a new one. Will also buy the reverse light Fix It kit from Clarks. Will see how I do with these new parts.

Other question I have as I am rewiring: there are two firewall grommet locations - I'll refer to them as the "low" grommet and the "high" grommet. I am trying to figure out which items go through which holes (fuel & fuel return, vacuum gauge hose, starter motor harness, main harness, battery cable).
I checked my assembly manual and didn't get a clear picture of how these lines should route.
Here is what I have come up with:
Low grommet: starter motor harness, battery cable
High grommet: body harness, fuel line, fuel return line, vacuum gauge.

Any pictures of correct set up would be great.

Thanks in advance.

I would not use the fix kit (3speed switch). I would simply wire to the 66 4 speed switch and into the normal 4 speed plug in the tunnel in the main wiring harness. Female bullet connectors should be able to be used to connect to the switch or you could find a used switch pigtail (big round rubber thing with the contacts for that switch in it from a used parts vendor like maybe Corvair Ranch or Steve Morton or similar source. The fix kit is funky and annoying. The stock switches work great. There is no polarity on the switch so it is just a matter or running 2 wires from the switch to the main harness plug. The melted wires are likely due to someone leaving the car parked in reverse with the backups running. I have seen this before. Had a buddies car start smoking at a car show because of this. Clark's and David Herrin III of The Source have replacement stock switches if yours is bad. You can find Steve and David on Corvair Owners Group on Facebook if you can not fin d them a different way.

[acarlson]

The 65 backup switch (shown above) will not work in the 66. You need C5365 from Clarks. The boot for the switch is another problem. I had the same problem as you. My 66 backup lights did not work. The previous owner had installed a 65 switch. I got the correct 66 switch from Clarks and got the connector for it from Jeff at Corvair Ranch https://corvairranch.com/

[bbodie52]

» Tue Sep 14, 2021 12:34 pm
...The melted wires are likely due to someone leaving the car parked in reverse with the backups running. I have seen this before. Had a bodies car start smoking at a car show because of this...

If the current draw for the standard pair of 1156 bulbs is such that the wiring harness can overheat, perhaps an investment in a pair of low-current LED bulbs would make sense as a safety precaution. They are bright and LED technology draws a lot less current, which translates into less heat buildup in the stock wiring harness.



iBrightstar Newest 9-30V Super Bright Low Power 1156 1141 1003 BA15S LED Bulbs with Projector replacement for Back Up Reverse Lights







https://www.amazon.com/iBrightstar-Newe ... NrPXRydWU=

‎LED, Mirror Lighting Type Automotive-exterior-side-clearance-marker-light-bulbs, Automotive-exterior-back-up-light-bulbs, Automotive-exterior-parking-light-bulbs, Automotive-exterior-brake-light-bulbs, Automotive-exterior-combination-parking-and-side-marker-light-bulbs, Automotive-exterior-tail-light-bulbs, Automotive-exterior-combination-turn-signal-and-fog-light-bulbs
Voltage ‎12 Volts
Wattage ‎3.8 watts

Customer Review: Brighter and smaller than the incandescent equivalent

IN COMPARISON...

SYLVANIA 1156 Long Life Miniature Bulb, (Contains 2 Bulbs)

https://www.amazon.com/SYLVANIA-1156-Mi ... 105&sr=8-7


Light Source Type Incandescent
Brand SYLVANIA
Manufacturer Part Number 1156LL.BP2
Brightness 402 Lumen
Wattage 26.88 watts

(ONLY ‎3.8 watts per LED bulb!

[joelsplace]

I'm with Ted. Don't buy the fix kit. If you had a '65 or earlier transmission and an EM Corvair I would recommend the kit but you don't have either.
The switch on the '66 up transmission is in a good location. No reason not to use it and you won't have any crazy add on junk that needs adjusting. The EM shift tube is exposed all the way back which allows the kit to work. The LM shift tube is enclosed so you would have to rig the Clark's kit switch either right at the shifter or outside the tunnel at the rear. Neither location is good.

[bbodie52]

Good advice. I only know of the existence of the "Fix-It Kit" from Clark's, but I never personally installed one. Now I know better! If your existing 4-speed backup switch checks out as functional with an ohmmeter, and the wire connections are intact, there is no reason not to use it. The 1965 and earlier switch seems to get damaged by impact and exposure often, but the 1966 design seems to be a little-more compact and perhaps less vulnerable to taking a hit. Good luck with getting everything working!

https://ssl.corvair.com/user-cgi/catalo ... w_page=84B

1961-1965 4-Speed Transmission Backup Light Switch


1966-1969 3 & 4 Speed Transmission Backup Light Switch

As far as your need for a power tap location to support your new backup light power needs, the fuse block has an open, unused spade connector that is labeled "HEATER" and appears to need something to do. You can connect to it with a new wire and a female spade connector. It already has a fuse large enough to support the heater fan plus the backup light circuit. Simply route a wire to the backup light switch connector, and you have switched backup light power (controlled by the ignition switch key position). Based on comments indicating that the original 20 gauge wire (20 DG) may be a little thin to support the continuous backup light current draw (without overheating), you might choose a thicker 14 gauge wire. As I mentioned earlier, it would not be bad to change the 1156 bulbs from incandescent bulbs to LED bulbs, to reduce the current draw from the backup lights. It looks like the LED bulbs will be brighter, too.

LEFT-CLICK EACH IMAGE TO ENLARGE FOR BETTER VIEWING...

1965 Corvair Fuse List and Fuse Block

1965 Fuse Block

1965-1969 Corvair Interior Compartment Wiring Diagram

» Tue Mar 09, 2021 5:00 pm

...Transmission/clutch may need some attention - grinding noise while downshifting into second gear, release bearing sounds a bit noisy and a bit of chatter when i start off from a stop...

Based on your comments, you may have one or two larger jobs in your future, if the synchro gears in the transmission are showing signs of wearing out or failure, and if your clutch is chattering.

» Tue Sep 14, 2021 10:59 am

as far as my non-turbo, 110 cylinder heads go, they do I have an oil cooler line from turbo unit to right hand cylinder head (see pic), I am assuming that the head builder (Ken) was aware these heads were going to be used on a turbo?? Hopefully the heads were redone with turbo in mind??

I would still check the cylinder head casting numbers to determine the true nature of the heads.

The turbocharged Corvair engine was early 1960s technology and had little in the way of sophisticated defense against engine detonation (fuel air mixture in the combustion chamber exploding rather than burning) The pinging sound of detonation occurring, if you hear it with the engine working hard under boost from the turbocharger, can be very destructive to the engine. (Back in 1970 I was driving up a long highway uphill grade on a bright, warm summer day in Southern California (the Conejo Grade from Camarillo to Newbury Park). I had the windows down and I was enjoying the feel of the turbo-powered Corvair engine. I failed to hear the detonation (pinging sound) because of the 70 mph wind noise, so my next warning came in the form of a hole melted in a piston! I made a phone call near the top of the grade. My mother drove out in the El Camino with a bumper-style tow hitch to bring her frustrated son and his broken 1966 turbo Corsa home.

The properly-tuned turbo Corvair engine has three things to prevent self-destruction...

1. High-Octane PREMIUM fuel.
2. A Pressure Retard device on the distributor, to retard timing under full boost (if it works).
3. An 8.0:1 Compression Ratio to reduce the possibility of engine detonation.

The final thing that can protect the engine is a knowledgeable owner/driver who does not overtax the engine's capability. The Corvair turbo engine was not really intended to run under long periods of turbo boost. It does better with short periods of blindingly-fast acceleration , followed by periods of rest. Proper tuning and proper driving habits, plus Premium fuel can keep your engine healthy. If your engine really has modified 110hp high compression ratio heads, it may be a little too easy to push your engine too hard and cause power-robbing, damaging detonation. I would not guess at this, but would want to find out, if possible. Cylinder head casting numbers are listed on page 5 of the attached CORSA Corvair Technical Guide 1+2 - Corvair Code Numbers.

[terribleted]

I'm with Ted. Don't buy the fix kit. If you had a '65 or earlier transmission and an EM Corvair I would recommend the kit but you don't have either.
The switch on the '66 up transmission is in a good location. No reason not to use it and you won't have any crazy add on junk that needs adjusting. The EM shift tube is exposed all the way back which allows the kit to work. The LM shift tube is enclosed so you would have to rig the Clark's kit switch either right at the shifter or outside the tunnel at the rear. Neither location is good.

Yup. I installed one of these before on a late model and have no desire to do it again period.

[jeffmort]

While I am still in fix it mode, I am not driving the car. Only driving I have done is nursed it to the DMV for registration and then to and from the paint shop. I am doing things a bit out of order but when the paint guy says "I can take your car now" - it's time for paint - didn't want to wait another 6 months.
I will be having the transmission, gear crunching/chattering issue looked at first thing by a qualified local Corvair mechanic once I have run out of fixes that I can handle on my own.
My list before any real driving:
1) Install new wiring
2) Fix fuel leak near tank (likely fuel return line)
3) Install fuel pressure regulator
4) Take car to mechanic for general check over: timing/adjust distributor/general tune up, cylinder head check, transmission/clutch advice, turbo function assessment and a general "once over" by a Corvair specialist that knows better than I how a Corvair should run.
5) Drive and enjoy

[jeffmort]

Sorry - my cylinder head casting number is: 3856762

[jeffmort]

Wait a minute - looking at your Corvair technical guide I do have 180hp turbo heads??
I swear I looked into this before and concluded they were non-turbo, 110 heads???
Happy accident I guess!