My driver side rear signal and brake light stopped working - I replaced the bulb, checked the fuses (fuses were fine), and checked the wire harness w/ the gage, and it is still not working. I checked the trailer outlet and there was no power coming to it, either. I'm out of ideas - help would be appreciated!

PS - everything is fine w/ the passenger side. :wtf:is going on?

Sounds like a rat ate the wire somewhere

Ok... A few question for you...

[*]Does your running light work properly? (Headlights on)

[*]Does the left and right turn signal work properly?

My first thought is the multi-function switch in the column is to blame because... If you turn on the left turn signal the brake light on the left side is canelled (disconnected) and allow the flash to control the taillight. Then all the wiring comes down the driver side frame rail and splices to the passenger. So if its a wiring issues both would be dead. So the problem is forward of the driverside bulb... Hence my though of the mutli-function switch.

Try wiggling the connector and the switch arm... But I think a contact wore plain and simple.

- so on the passenger side all is fine front and back!- on the driver side the front is fine but the signal go fast- the problem is the driver back side. i have only the taillight on, but the brake and the signal are not working. even with new bulb.

This might help you out.

I'd start at the taillight and move forward. There is a connection to the taillight housing that you can get to from underneath the truck by the rear bumper. I'd use a test light to see if you have good power to that connector and a multimeter to check resistance through the ground wire. If you've got power but no ground, add a ground. If nothing there, check the right turn signal at the 7-pin connector. Do you have power there? Right turn is usually the pin at about the 3-o'clock position, IIRC. Nothing? Move upstream to the next connector. That video shows another connection along the frame rail someewhere. I don't remember seeing one like that, but you may be able to isolate the turnsignal wires at another connection block. I'd check these easy ones before I tore into the column or the fuse block.All the wiring runs along the left side of the truck along the frame rail, The wiring to the right rear taillight runs across the spare tire carrier crossmember. I'd also drop the spare to make sure it isn't pinching the wires somewhere. bb

thank you for your advice - but i'm still trying to figure out what is wrong w/ my lights. i did all the above, and i found out that i have tail, brake, and signal power to the 7 point connector - but, the left signal is still fast. i dropped down the spare tire & i checked the harness for twisted/cut wires, and it checked o.k. I also checked all the connectors & wires w/ the gage in several areas along the rail all the way to the front, and i found that i have power, but still, the left signal is running fast. after all this investigation i think that my problem might be the multi function switch. where is the best place to get a multi function switch? (my dealer asking $150)

I have a known good spare you can use for the purpose of testing. If you pay shipping and a $25 deposit I'd be more than happy to send it along. You can also get aftermarket ones for $50 online. You can see how I disassembled one and checked continuity for the hi/lo beam function in this thread. You could easily figure out how to test continuity for turn signals. But I cannot imagine how this could be the MF switch. I don't think separate circuits (for front/rear) run through the switch. This may sound stupid but is the bulb making good contact in the socket? Also, a bulb that does not draw enough (like an LED) will flash fast. Is it the correct bulb? bb

I had the same thing happen to in my 1994 full size Blazer. All the parking and left turn signals worked just fine but the right rear. Checked all the fuses, bulbs, sockets, and the multi-function switch. I finally got underneath it, inside the hood, and under the dash and checked all the wiring and finding the brake/turn signal wire. After it comes out of the firewall and starts back, I found a short section of it that had rubbed against a sharp edge of the inside of the fender and actually cut that wire in two. Hope that helps before you go spending a lot of money.

PROBLEM SOLVED!!!! Thank you all for your help and your advice - so i decided that i couldn't take it anymore - so i dropped my spare tire & started from the back of the truck checking the harness & i found the left rear wire cut because it was rubbing against the rear shock (there was not enough sleeve) Now its working perfect! again thank you all for your help

At least it was a easy fix...