# Any Chevy S10 Guru's Out There? (Or Car Enthusiasts In General)



## bubbler (Oct 18, 2010)

Did you actually check for voltage at the socket? Many times I've found something not working and it turns out to be the socket itself...


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## crankbait09 (Mar 26, 2011)

bubbler said:


> Did you actually check for voltage at the socket? Many times I've found something not working and it turns out to be the socket itself...


ok, work with me bubbler  , are you talking about using a voltmeter? placing the red in the socket base and placing the black probe on the frame of the truck???? what type of voltage should I be seeing? does the brake need to be pushe din or the blinker on?


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## 47_47 (Sep 11, 2007)

You will see ~12.6v dc (battery voltage) with the engine off and approx 14.5 v dc engine running. You will need to depress the brake pedal or activate the turn signal when checking voltage. The ignition key must be in the run position for the turn signal to work. 

The ground is common to both the stop/turn and tail lamp. If the right tail lamp light works and the right stop/turn do not, the ground is not the problem.

Did you put in the correct bulb? 
GM did have problems with the tail light circuit boards on earlier models.


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## crankbait09 (Mar 26, 2011)

ok, then the tail light works fine....it's definitely the brake and turn signal.

I swapped out the bulb with a new and when that didnt work, i took out the left turn signal lamp and placed it on the right side to see if it would work........it doesnt.

I will test it tonight with a voltmeter and see what happens.


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## D-rock (May 23, 2011)

Probably a burnt up socket. You can use a test light to check it, or a lot times it will be black inside it.....


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## crankbait09 (Mar 26, 2011)

what is a test light and how does it work?


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## bubbler (Oct 18, 2010)

crankbait09 said:


> what is a test light and how does it work?


OK, so the idea here is that you can replace the bulb w/ a known good one and it still will not work if the socket has gone bad--either corrosion, or bend contacts, etc...

What I'd suggest is getting either a voltmeter or a 12V test light (available at auto-parts store, you should be able to find one VERY cheap, they are almost give-away level for the truly cheap little ones that feature just an LED).

The test light will "light up" when 12V is present. The voltmeter will read ~12V.

Whatever bulb is not working, find that socket, switch on whatever switch is necessary to make that bulb light up (i.e. if it's a turn signal, turn on the turn signals--btw you also try the hazards if you think it might be the turn signal switch itself). I would BACK PROBE the socket... this means that you shove your test lead into the back of the socket (where the wire is going in) to try to make contact. You may want to do this on a socket with a bulb that is working, that way you get the feel of your test light or voltmeter working... 

I've had good luck with shoving an unbent paperclip, or very long pin, in there to get contact--just be sure you don't short it out!

For a ground you can use the metal truck body.


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## crankbait09 (Mar 26, 2011)

I have stuck a volt meter on the socket.......nothing. I have cut the wires at the socket to see if I was at least getting power to the socket.......nothing.

I have stuck the meter on the left side and that checked out fine.

I will try one more splice point on the left side of the truck to see if I am at least gettingpower to that point before it branches off to each light.

any other thoughts?


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## 47_47 (Sep 11, 2007)

Narrow it down. Trace the harness and test for voltage at each connector. Check the connectors for corrosion and terminal tightness. If the truck was in an accident, look in that area for chaffed and corroded wires. Also look where the harness takes sharp bends and can possibly chaffe.

This is not hard, but can be time consuming. Good luck.


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## crankbait09 (Mar 26, 2011)

47_47 said:


> Narrow it down. Trace the harness and test for voltage at each connector. Check the connectors for corrosion and terminal tightness. If the truck was in an accident, look in that area for chaffed and corroded wires. Also look where the harness takes sharp bends and can possibly chaffe.
> 
> This is not hard, but can be time consuming. Good luck.


I was going to begin tracing it tonight. The harness that this goes back to has a connector with 5 pins in it. How do I know which pin is going where? It hits this harness then branches off to each light. Just because I'm getting "power" doesnt mean that I'm going to know which light it's going to. I can show pictures of what I am talking about if needed.


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## 47_47 (Sep 11, 2007)

The wires are color coded. Check at the socket for what color is what. Black is ground, both left and right tail lamps should be the same color and the other color at the right rear will be the directional and stop.


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## bwilliams (Jul 4, 2012)

What year is this truck and have you solved the problem?


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## crankbait09 (Mar 26, 2011)

2002

It has been put on hold but I will be tackling it again here in the next couple days.......

Once I pull it in to the garage, I will be able to tell more..........


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## bwilliams (Jul 4, 2012)

Have you ever heard of a tool called a Powerprobe. This would allow you to test for B+, ground and the bulb all at the socket. Once you determine which circuit is bad, you can work your way back. With a proper functioning circuit, you could see roughly 6V as an average voltage. That is because it is 50% on, 50% off. Generally, left side wiring is going to be yellow and right side will be green. I will see if I can find a wiring diagram and help you out. I'm off to the Indy tomorrow so probably won't be until Sunday that you hear from me again. Powerprobe. Watch Youtube. Best tool ever...


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## crankbait09 (Mar 26, 2011)

that tools friggin awesome..........Until I can purchase one, i will use the handy dandy voltmeter......
I will try it this weekend..........please stay tuned


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## bbo (Feb 28, 2010)

have you tried checking/replacing the turn signal flasher?

part is ~10-15$


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## crankbait09 (Mar 26, 2011)

bbo said:


> have you tried checking/replacing the turn signal flasher?
> 
> part is ~10-15$


are you talking about the actual lamp socket? If so, yes. There is nothing wrong with it......


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## bwilliams (Jul 4, 2012)

Okay crankbait, here is what you need to do. If you don't have a Powerprobe, you need to establish which circuit has gone bad. Take a jumper wire and go from the battery negative post and jump it to the black wire coming out of the socket with the turn signals on. If the circuit begins to work. There is a break in the wiring between the socket and the ground point which should be the rear of the frame rail. If that does not work, we need to go to the positive side of the circuit. Take your jumper wire and put one side on the positive post of the battery, and take the other end and touch the yellow (left turn) or green (right turn) wire coming out of the socket. The lamp should come on steady (TS switch off). If it does, we need to work our way back from there. I'll check back tomorrow night. You may need to backprobe the connector to amke the connection. Do not pierce any wiring. Jump these wires only momentarily. Be careful not to touch any grounding points (metal) during testing of the positive side.
crankbait-Make sure you heed the warning above. I am not responsible or liable for anything you do. I am just saying that with the equipment you have, this is what I would do if I had to diagnose this problem with limited resources.


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