turn signal help
 

I just had new tilt column installed in my '72 GMC. All turn signals worked for awhile. Now, the right front turn signal, the right front side marker light and right turn signal dash indicator do not work. The left side is fine. Where do I start? I do have a third brake light with a logic unit, but the left side is working fine and the right rear tail light is working fine. Do I have a faulty turn signal switch? Or what? Thanks for any help.

Re: turn signal help
 

Does the right rear light flash OK with the right turn signal on?

First thing to check is the bulbs, make sure they actually work when you insert them in another socket or use test wires. Perhaps swap left to right.

See if you get different results for right front with the hazard flashers.

Check the wiring to see if it is in good shape. Some of the wires run inside the driver side fender where rats like to chew. Check it out.

Look for the under dash curved connector for steering column. Here are the wire colors for wires that go into under-dash harness:

purple - power from turn signal flasher
brown - power from hazard flasher
white - brake light power
black - horn button
light blue - left front turn signal light
dark blue - right front turn signal light
yellow - left rear turn signal/brake light
green - right rear turn signal/brake light

Use a test light probe or multimeter to check for expected voltages by inserting probe into the back of the connector while it is connected to the steering column.

Re: turn signal help
 

Yes, right tail light does flash with right turn signal on. As I went down your list of things to check, I found what appears to be a loose connection in the curved connector for the steering column. Upon wiggling the connector the right turn signal starts to flash and things are normal. I'll check what's up with the dark blue wire. Thanks a bunch for the troubleshoot. At least I won't have to tear the steering column apart and replace the entire switch. Thanks again!