Corvair Forum

Here's the next chapter of the ongoing saga of my son's 61 sedan. It has started to act up occasionally while driving. First the radio cuts out, and then the motor tries to die. The gen/fan light comes on and if I tap the accelerator the engine picks back up. I have been unable to figure out cause due to the intermittent nature. I am thinking it may be a problem with fuel delivery, but then I can't explain why the radio cuts out. Any ideas?

There are main electrical connector plugs in the wiring harness, one in the engine bay, and one above the gas pedal. If there is corrosion on the pins, you might be getting an intermittent disconnect which would kill anything electrical, including the radio, then the ignition. Use some contact cleaner on the pins and be sure the connection is tight.

It sounds like an electrical problem. The radio cutting out, the motor dying and gen/fan light comes point to a lost electrical power. Then you tap the accelerator and it picks back up what's happening is; as the engine revs up the generator spins faster and gives the electrical system a little more current. My first guess would be the voltage regulator. Have you swapped out the voltage regulator? Also look for a bad ground and loose connections.

The multi-pin plastic connector in the engine compartment is usually the first suspect. It is exposed to heat and vibration, and moisture if the engine is cleaned and rinsed. Over the years the metal contact pins inside the connector can develop corrosion and the connector itself can loosen. Sometimes just unplugging the two halves and then reseating them back together will clear the problem, but you should inspect the metal pins inside when you separate the two halves to look for damaged or loose pins, or signs of corrosion on the metal surfaces.

The wiring diagram shown below is for a 1962 Corvair, but it is typical for all EM model years. The 8-pin multi-connector shown near the bottom of the diagram is the connector that is of concern. The 12 gauge wire that connects from the battery positive terminal to the voltage regulator carries power for all circuits within the car, with the exception of the primary high-current feed to the starter motor. A second 10 gauge wire is shown routed from the same connector on the voltage regulator to the multi-pin connector. This wire ties to the fuse block and the ignition switch, and provides power to all switched and unswitched circuits in the car. Other circuits affected by the electrical connections that pass through this multi-connector include engine ignition circuits, charging system warning lights, tail lights, etc. So a poor-quality, intermittent, or loose connection in the multi-connector can disrupt power and operation throughout the car. The multi-pin connector in your Corvair is over 53 years old, so you can imagine how things could deteriorate within the plastic and metal connector over the years.


The Clark's Corvair parts online catalog electrical section begins on page 97 (shown below). This page describes some of the common issues associated with aging electrical connectors in Corvairs. Page 100 describes the specific multi-pin connectors and also mentions "electrical grease" as a recommended compound to help prevent dirt and corrosion from forming...

http://www.corvair.com/user-cgi/catalog ... ow_page=97


http://www.corvair.com/user-cgi/catalog ... w_page=100

Thanks for the info. I'll be checking that connector today.

Well apparently I can't catch a break with this car. I checked the connector mentioned above and found that one of the pins was dark. Scrubbed up the pins and reconnected. The problem continued. Yesterday, my son went to get some food and when he came out the car wouldn't start. Just went down to try and bring it home. I switched batteries thinking that was the source of the problem. Turned the key and there was nothing. No lights, no click from starter, nada. If the ignition switch crapped out, would that account for this issue? For clarity, I have switched over to an alternator, but still have the original point type ignition.

I'm hoping that this combined passenger compartment and engine compartment wiring diagram helps a little with your troubleshooting and fault isolation process.

The symptoms you observe can often lead to the source of the fault. For example, some circuits are "hot" all the time,as long as the battery is connected. Other circuits are only "hot" when the key is in the ON position, as these circuits are switched power circuits that only operate when the key is ON. If you trace the path of electricity from the battery positive terminal, past the voltage regulator, and through several connectors to the passenger compartment, you can see why some circuits — such as headlights, taillights, brake lights, the horn, and the cigarette lighter are powered at all times — even with no key in the ignition. Other circuits — such as the starter solenoid, turn signals, radio, etc. are switched-power circuits that are controlled by the ignition switch. Those circuits only receive power when the key is in the ON position (from the ignition switch "C" terminal), or in the case of the starter solenoid from the ignition switch "S" terminal (with the key turned to "START").

When you state "no lights", are you indicating no instrument panel lights or no headlights or tail lights? No horn? If these circuits are not functioning, the power interruption is occurring BEFORE the ignition switch (or there is a problem at the other side of the battery with the GROUND connection).

If the headlights, horn, brake lights, etc. all function, but the starter does not click when the key is turned to START, the problem is further down the circuit — as with a bad starter switch, bad connection to the solenoid, bad solenoid, etc.

So understanding how your car wiring works normally will help you to determine where the cause of the interruption is likely to be. Your troubleshooting direction can begin at the wiring diagram, to help you to clearly define the symptoms and to interpret those symptoms to decide where to look for the cause of your problem.

So if you have no lights, no horn, etc., your GROUND is faulty or you have no POWER getting to the passenger compartment. If the chassis ground is examined and proves to be good, and the battery is good, the eight-pin connector in the engine compartment becomes suspect. If you confirm power is getting through that connector, the next six-pin connector in the passenger compartment becomes suspect.

Left-Click each image to enlarge detail for better viewing...

I hope this helps a little. Perhaps carefully studying the electrical path from the battery on the wiring diagram will help lead you to the trouble point. If you are still not certain, please clarify your description of the symptoms so that I can perhaps help with interpreting them to try to point to the next step in troubleshooting.

If you have no power in the car at all, as in no headlamps, interior lamps horn etc. You problem is almost certainly between the battery and the ignition and fuse box. The 12B (12 gauge black) wire from the battery in the above diagrams feeds the entire car (the only exception being the large gauge cable that runs directly to the starter). It runs to the voltage regulator and continues becoming the 10B (10 gauge black) wire that enters the top right pin in the 10 pin multi connector in the right page of the above diagram. (if you have installed an alternator and eliminated the old voltage regulator there still must be power directly from the battery to this spot). This connector is located in the left front of the engine bay. Often the contacts in this connector on this particular wire get corroded intermittent contact. No contact no power. The 10B wire continues forward thru the main body harness from this connector to a similar connector at other end of the main harness. That connector physically located under the dash near the accelerator pedal (possibly behind the steel cover that covers the cables and pulleys as they come up out of the tunnel and floor), can also corrode the same way. A bad connection or break anywhere along this wire will cause a no power situation. Use a volt meter to check (starting at the battery) (hook negative of volt meter to the negative post on the battery and probe the connection with the positive lead on the meter) from battery to each connection along the way, ensuring the power is getting past each plug or splice all the way to the ignition switch where it should be a 12R (12 gauge red) wire. When you get to a spot where there is no 12Volts you problem lies between the last good 12V reading and the spot that does not have 12V. This wire is hot all the time so no turning of keys etc. are needed and there are no breakers or fuses along the way.

Another possibility is a bad ground connection from the battery to the body and engine. Battery posts must be clean and the negative cable must have contact to the left frame rail below the battery as well as a large gauge connection from the battery or frame rail to the engine. (lack of connection to the engine itself will not cause total loss of power in the car, but, is essential for proper engine operation).

Made some progress, but developed a new problem. I ended up completely smoking one of the pins in the 8 pin connector. It was the one with the large black wire. Today I simply bypassed the connector and the car turned right over. When I put the key in the ignition, I heard what sounded like electricity arching in the dash. Pulled the ignition switch out to check the wires and found that the large red wire's plastic coating was really messed up. Looks like it has been going bad for quite some time.

I can't seem to find where the wire goes from the switch. I plan on tracing it back, however far I need to go, and then just replacing it. Does it join up with the engine harness or the front harness.

The large black wire you described at the multi-connector provides 12V DC to all circuits throughout the car (except the starter motor). It originates at the battery positive terminal, and connects to the voltage regulator BATT terminal. At this same connection point it ties to a 10 Gauge Black wire that links to the engine compartment multi-connector, passes through it, and on to a wire junction point in the wiring harness near the instrument panel. From there it branches out as a series of Red wires in various gauges that feed the fuse block, cigarette lighter, ignition switch, light switch, etc. (all points that require 12V DC at all times — unswitched).

You will need to determine what caused the connector at the ignition switch to deteriorate. A significant amount of current passes through it at that connection point. It is possible that the connection was corroded or loose, which could have caused arcing or heat buildup at that point and perhaps further damaged the connector over time. Does the switch look damaged, or just the connector? If the wire harness insulation and the switch seems undamaged, simply replacing the end electrical connector with a new one may be all that is needed.

Not sure what caused the damage to the multi-pin connector in the engine compartment and the damage to the connection point at the switch. A short to ground at some other location could cause too much current draw and could overheat the harness, or there could be a breakdown at these two connection points caused by age, corrosion, a loose connection, etc. If you repair or bypass these two connectors and everything functions properly without further signs of overheating, arcing or damage, you might be OK with just repairing these faulty connection points. If there is any sign of overheated or melted insulation on the wiring harness you will need to inspect the wiring further to locate the cause.

The primary voltage distribution path is shown below for the unswitched circuitry that is distributed from the wiring harness tie point when the battery voltage enters the passenger compartment from the engine compartment...

Thanks for the info. The purple wire and the green wire appear to be fine, but the insulation on the red wire shows a lot of melting. Hopefully I can get the wires traced today to see how much replacement will be necessary.

Next question, bear with the mechanically challenged, has to do with the ignition switch. I have three wires; red, purple and green. I figure the red one goes on the post labeled "bat". Where do the other two go. There are five posts on the back of the switch and I don't want to get anything crossed up.

If you look at the wiring diagram I posted earlier, you will see a representation of an ignition switch near the top-center portion of the diagram. There are three wires connected to it, with the terminals labeled "R", "S", and "C".

R - Connected to the main power source tie point in the wiring harness via a Red wire. Receives continuous 12V DC from the battery positive terminal and the charging system (generator or alternator).

S - Connected to the starter solenoid at the engine via a Purple, or Violet wire. When you turn the key to START, power is applied to the "S" terminal on the switch, which energizes the starter solenoid and cranks the engine. When the engine starts and the driver releases the spring-loaded switch, the key returns to the ON position and the starter disengages.

C - Connected via a Green wire to another connection junction point in the wiring harness that provides power to switched circuits that only have power when the key is ON. If you follow the wires you will see they provide power to circuits such as the GEN and OIL PRESSURE instrument panel lights, the fuse block to power other switched circuits, and the ignition coil to provide an ignition spark to the engine spark plugs via the distributor.

Once again, a whole hearted thanks for the information ya'll have given. I was successful in hooking up the ignition and it now starts without any scary electric arcs.