Identifying electrical wires in LM

Anything Corvair related
Posts: 4
Joined: Sat Aug 08, 2020 10:54 am

Re: Identifying electrical wires in LM

Post by mg9184 »

Thanks again for all the helpful information, I realized that the reason I couldn't find the brake light switch was because it was simply missing. I replaced the brake light switch, all of the rear bulb sockets, and any blown bulbs I could find with parts ordered from Clark's, and I made sure that the bulbs were the right type for each socket. Now almost everything works properly, except for the rear left hand turn signal/brake light and the rear left side running light, I think part of the wiring harness might have just corroded, because I've done everything else to make sure the bulb would light up.

Posts: 1164
Joined: Wed Oct 13, 2010 12:51 pm
Location: Northlake, TX

Re: Identifying electrical wires in LM

Post by joelsplace »

That very well could be wiring but have you thoroughly checked the grounds?
113 Corvairs, 5 Ultravans and counting
Northlake, TX

User avatar
Corvair of the Month
Corvair of the Month
Posts: 9710
Joined: Mon Aug 06, 2012 12:33 pm
Location: Lake Chatuge Hayesville, NC

Re: Identifying electrical wires in LM

Post by bbodie52 »

...except for the rear left hand turn signal/brake light and the rear left side running light...
The 20Y wire powers the left turn signal/brake light. A test with a multimeter should show if voltage is making it to the socket or the 12-pin multi-connector (firewall side/engine compartment side). The point of origin is the round Camaro-style multi-connector at the output of the turn signal switch at the steering column. The power sources are different (flasher and brake light switch). You already know that these voltages are making it into the turn signal switch, because the brak/turn signal bulb on the right side works. So the question is... are thos voltages coming out of the steering column switch for the left side?. The brake light switch is normal-through for both rear lights when the turn signal lever is in the middle (neutral() position. Unless there is an internal bad contact in that switch, you should find the brake light voltage coming out of the steering column on both the 20Y and 20DG wires (2nd and 3rd from the bottom in the diagram). It goes in via the bottom connector (brake pedal switch) abd back out frm the next to connectors to the right an left rear lights. The violt flasher feed is the 4th from the bottom, and is output only with the lever is moved to the left or right.

If you find the voltages output from the source (steering column), check bat to the engine compartment to see if it is making it to the 12-pin multi-connector. If that connector is the point of interruption, check for internal corrosion or bent/damaged metal contacts.
Most rear circuits route through the engine compartment multi-connector (below the voltage regulator, near the firewall). The number of metal connector pins inside depend on the Corvair model year, ranging from 8-12 pins. This rear multi-connector is a common source of trouble, as it is subjected to age, vibration, heat, and moisture for many years. Even when the outer plastic shell halves appear to be tightly connected, the internal metal pins may not be providing good electrical connectivity, as they may be loose, dirty, corroded, or bent.

:link: ... ric+grease
Permatex 22058 Dielectric Tune-Up Grease, 3 oz. Tube

The left and right side marker lights get their power from the same source as the license plate light and the left/right tail lights. If all of these lights are functioning except the left side marker, check the bulb, socket, and socket ground.




Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible

Post Reply

Return to “Corvair Talk”