# Rear Brake Lights/Turn Signal Lights Problem



## pspeir

Hello! I have a 1993 Blazer S10 and for some reason my rear brake lights and turn signals have stopped working. The bulbs are fine and the fuses look good. The front turn signal lights work, so it wouldn't be a fuse for them anyway (I believe.) I'm hoping there may be a simple solution as I really don't have money to put this car in the shop, and it is my family's only car so we can't afford not to drive it. 

Thanks in advance for the help!


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## kjms1

brake light wiring goes thru the turn signal switch for the rear
going to need a test light or a known good turn signal switch that you can plug in real quick and test to see if it works 
with the test light key on turn on left or right turn signal, at the connector plug on the steering column probe each of the wires you should have 2 of them flashing
one flashing,,, needs a new switch 
two flashing,,, bulb bad or wiring prob form the connector to the back lights


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## pspeir

Thanks for that. While it (almost) makes sense, it seems beyond my capabilities. Probably will need to take it in to a service center.


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## Midnight Tech

Does it have a towing harness on it?


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## kjms1

since you think your out of your league to check it 
have you tried a new bulb or have you just looked and think its ok by looks

dont remember if the Blazer has the same connector plug at the bulb as the P.up trucks but the trucks had a lot of problems with the plug connector 

check the connections and if it has the tow package connector underneath it like Midnight is suggesting

Go buy one of those cheap test lights about $10 bucks turn the turn signal on and remove the bulb and touch the contact inside the socket and see if the test light starts flashing


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## Raylo

Those switches are crappy and I had to replace them on my 1994 Camaro and 1994 S10 p/u. On the Camaro the only thing wrong was my brake lights quit working. A look at the schematic showed that this switch was the only common point for a single fault to cause both brake lights to be out.

I don't remember all the details but it really wasn't that hard a job. I believe the procedure was in my Haynes manual and the 1 trick that makes it easy is to loosen the steering column nuts to allow the column to be raised so the old connector can be removed and the new one threaded in to the channel under the column. I did the Camaro w/o doing this step and got it done, but it was difficult. I didn't repeat that mistake when I did the truck. BTW, the part is pretty cheap and can be had at Advance, Pep Boys, etc.


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## pspeir

Good advice all around. I did check the bulbs, replaced them and still not working. It does not have a towing harness. I really appreciate all this. Today I'll get the test light and after looking at the turn signal switch it doesn't look too difficult. I'll give it a shot if the test shows it's necessary. Thanks again for the help!


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## pspeir

Okay, got the tester and took out the bulbs--the turn signals lit up but not the brake lights. Possibly I got a couple of bad turn signal bulbs? Nothing to do, I suppose, but get some more. Excuse the ignorance, but there are three lights on both sides of the rear light assembly. The middle, I'm assuming, is the turn signal. It lights up. The bottom and top do not. The top on both sides has a thick yellowish gunk inside that I think may be corrosion, so it's possible that's the problem...? The bottom lights do not have that problem but I can't get anything with the tester, so perhaps there's another problem. As the middle lights up with the tester, I'm thinking it's not the switch after all. Any other suggestions?


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## Midnight Tech

The yellowish gunk is a dielectric grease put in there at the factory to keep it from corroding...does it have 3 individual sockets with wires or a "circuit board" for the lights?


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## pspeir

It has 3 individual sockets with wires.


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## Midnight Tech

Bottom light on each side should be back up bulb. Will the top ones light up at all (park lights)?


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## pspeir

No, they won't light up at all. I just stuck the tester inside the fuse for the lights and got nothing. The fuse itself looks fine, but again I'm getting nothing when testing the fuse box.


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## Midnight Tech

Just hit me - is the CHMSL (3rd brake light) working?


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## Basementgeek

Did you also check the ground to these bulbs?

BG


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## pspeir

I don't believe I have a third brake light. If you mean one in the middle, above the window or in the window, then no I don't have one.

I was finally able to get something out of the top light. I put on the hazards and put the tester in--didn't light up but the car began beeping. So I put a light in and when I pushed down hard on the light it lit up. So I pushed down on the brake and pushed down on the light and got a light. Possibly the sockets are bad? I didn't realize the turn signal was the same light as the brake...seems a bit odd to me.


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## Midnight Tech

Most of the older cars used the same bulb for both, but later models have gone to separate bulbs in most cases.
I'd be tempted to go ahead and replace those sockets then you'd know it was getting a good connection.


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## pspeir

I bought the sockets and was about to replace it as well as add new bulbs when I decided to clean off some of the gunk. I did so, found some corrosion and cleaned that off too--on both the right and left side. Added new bulbs and what do you know--it worked! Man I feel a bit foolish for not thinking of that first, but regardless you guys have been wonderful. Thank you so much.


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## Midnight Tech

Sounds like the dielectric grease missed a spot...get a tube of this from the parts house and put some on the new bulbs and hopefully this won't bug you again...but I'd keep the sockets-just in case.
BTW, if you put some of that grease in your spark plug boots and smear it around, it'll make getting them off the next time a lot easier.


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## Teresa57

I had a similar problem with my Ford Explorer not long ago. You said in your original post that the Blazer was your only car. Can I ask do several people drive the car and change the position of the tilt steering? This will effect the wiring for the blinkers especially if your car is older ( dry rot). This problem cropped up for me when I was teaching my daughter to drive and she adjusted the steering wheel to where it was comfortable for her. Fortunately, I was able to find a position to keep the steering wheel in, that I guess gave the wires the best connection and the problem stopped.


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## wolfen1086

Man I wish I'd seen this thread sooner, S-10 Blazers from 82-93 are right up my alley since I had an 89 for 10 years


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