Brake lamp switch

[Magic1]

I recently rewired my 82 Sierra and had everything working. But now I've lost my rear turn signals as well as brake lights. Everything else is still working fine. I'm going to try and trace the wires to find the problem but before I do I was looking through my instructions that came with the harness and realized that the brake lamp switch is connected in with the turn signals and was wondering if the brake lamp switch had gone bad if it would cause the brake lights and the rear turn signals to quit working or only the brake lights themselves. I've never been good with wiring but the instructions were very straight forward and I had no problem with the installation but trouble shooting is not my strong point. 

[rich weyand]

Check your grounds.  There should be a ground from the driver side tail light housing to sheet metal.  Make sure it is present, that it is clean and making good contact.  On some models there is also a sheet metal ground on the passenger side housing.

Next check your ground between the driver side frame rail and the engine block.

[Magic1]

I've checked the grounds at the tail lights. They all seem fine but I would have thought if it was a ground problem I wouldn't have rear lights at all. The tail/backup lights are working but the brake and rear turn signal lights aren't. When I wired it all up I ran a ground strap from the battery to the engine, from the cab to the back of the engine and from the engine to the frame.

[rich weyand]

The ground strap from the engine to the frame is normally on the driver side.

You have the big three up front.  You have the grounds at the tail lights.  So that's good.

The circuits that are misbehaving are the DK GRN-19 and YEL-18 wires in this diagram.
http://www.73-87chevytrucks.com/techinfo/wiring_diagrams/81-87_chass_rr_light.jpg

They go forward to the engine bay, through a bulkhead connector, to the steering wheel switches in the center of this diagram.
http://www.73-87chevytrucks.com/techinfo/wiring_diagrams/81-87_cab_inter_pg2.jpg

I believe that connector (to the STRG COL SWITCHES) is at the base of the steering column.  Can you disconnect that connector and use a test light to test the operation of the DK GRN-19 and YEL-18 contacts of the steering column connector at that point?  That would isolate the problem to the wiring to the back, or to the wiring and switches in the column/panel/pedals.

[Magic1]

The ground strap from the engine to the frame is normally on the driver side.

You have the big three up front.  You have the grounds at the tail lights.  So that's good.

The circuits that are misbehaving are the DK GRN-19 and YEL-18 wires in this diagram.
http://www.73-87chevytrucks.com/techinfo/wiring_diagrams/81-87_chass_rr_light.jpg

They go forward to the engine bay, through a bulkhead connector, to the steering wheel switches in the center of this diagram.
http://www.73-87chevytrucks.com/techinfo/wiring_diagrams/81-87_cab_inter_pg2.jpg


Now when you say at the base of the column are you talking about the pigtail that plugs into the steering column about halfway down under the dash or are you talking about the very base of the column where the neutral/safety switch is? Sorry for the confusion but looking at those diagrams just daze me. Lol.
I believe that connector (to the STRG COL SWITCHES) is at the base of the steering column.  Can you disconnect that connector and use a test light to test the operation of the DK GRN-19 and YEL-18 contacts of the steering column connector at that point?  That would isolate the problem to the wiring to the back, or to the wiring and switches in the column/panel/pedals.

[rich weyand]

The pigtail that plugs into the column about halfway down.  The pin numbers you want to test are 18 and 19, the second and third pins from the longer end of the connector.  The connector has a gap in the middle, with fewer contacts on one side, and more on the other.  It's the longer end where 18 and 19 are.

You just use a test light, grounded on one end, and test the connector on the steering column, not the plug you pull out.  Once the test light is in place on a pin, see if the test light works properly, as you want the tail lights to work.  If it does, then the problem is between the column and the back of the truck.  If it doesn't, then the problem is probably in the steering column.

You need to learn how to read those diagrams if you are going to own one of these trucks and keep it running!

[Magic1]

Yeah I need to study up some more on the wiring diagrams. Lol. I know what you're talking about though. I wired that plug up. I was just wondering though before trying to pry that thing off the column and use a test light if the brake lamp switch itself could be causing the problem since the brake lights as well as turn signals run through that switch.

[rich weyand]

Yeah I need to study up some more on the wiring diagrams. Lol. I know what you're talking about though. I wired that plug up. I was just wondering though before trying to pry that thing off the column and use a test light if the brake lamp switch itself could be causing the problem since the brake lights as well as turn signals run through that switch.

Easy enough to check.  Pull the plug off the switch, and try the turn signals.  Short the plug, note whether the brake lights are on, and try the turn signals.

[Magic1]

Alright.  Once I get a chance to try it out I'll post back in here with what I've figured out so far. Appreciate all the help.

[VileZambonie]

Check the wiring harness connection on the drivers side below the brake booster area. It's probably unplugged.

[rich weyand]

Check the wiring harness connection on the drivers side below the brake booster area. It's probably unplugged.

I think that would kill his tail lamps too.

[Magic1]

I checked it the other day at the back of the circuit block under hood just to be sure and they were all good and snug.