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Having issues with back lights on 96 chevy s10.

25189 Views 17 Replies 7 Participants Last post by  eric32
Hello guys I hope someone can help me out on what to look for. I have a 96 chevy s10 2wd and I am having problems with the back brake lights not working. I have turn signals, lights come on when I put on the head lights and flash when the turn signal is on.

I am just not getting brake lights now. Fuse is ok in the fuse box. I got this truck last summer and who I bought it from had the rear tail light wires all cut up and it looked like it had a trailer hookup on it. Well my dad cut it off cause I was having all kinds of issues with my light's not working right. Everything works right in the front but the back is a different issue.

My dad checked out all the wires and he know just about everything about cars etc. Ok looking at my truck underneath there is a hookup piece that has four wires. Yellow, dark green, light green, and brown are the colors.

After that there is on the driver side coming from my tail light assembly 1 yellow wire, 1 light green wire, and two brown wires and of course the black for ground.On my passenger side there is 2 brown wires, 1 light green wire and 1 dark green wire and of course the black ground wires. The ground wires is ok. After my dad rehooked everything back up I had turn signals, brake lights, and tail lights when the head lights was on.

But here is the funny issue I had since last summer after all that was done if I turned on my left turn signal and put my foot on the break it would stop flashing and would just pause and after I took my foot off of the break pedal it would flash again. So tired of having people getting angry with me when I make a left turn with it being paused cause I have to have my foot on the break I tried to manually flick the turn signal stick up and down just enough to try to make it look like its working but on the front everything is ok but the dam thing would go on and off when I flicked it manually on the passenger side!!!.

Ok this morning I wanted to try to see if I could find out whats wrong and why the left turn signal would pause when I put the brake pedal on. Well all I did was un hook my wires at the back 4 wire hookup as listed above and could not find anything wrong that I could tell.

The two light green wires are connected together to the one light green wire at the hookup and the yellow is hooked up with the yellow and the brown is all hooked up to the brown wire. Looking way past the 4 wire hookup harness there is a thick red wire that is not hooked up to anything and also a thin dark blue wire and another thing light green wire that is like the ones in the back on both sides.

Well I did not change anything. Now the left turn signal works just fine and does not pause if I put my foot on the break on the left side. But now when I push my break pedal down I have no break light to come on just on my cab. I really hope someone can help me out on what I need to do and check. I don't know a whole lot about automotive wiring just hooking up stereos.From what it looks like underneath that 4 wire hookup piece was not orginally there.Please anyone?
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You should get a diagram for the vehice and check all the wires that were re-connected first.
Check for power at the brake light switch
Check the turn signal switch, the brake lights go through this switch. This is a high failure item on an S10.
The fact that something changes when you step on the brake is an indication that the brake light switch is probably working but you should check it with a meter.

trying to track down an electrical issue without a diagram is very difficult. You should be able to find one on line
Well I have got a hanes manual and all of my wires that need to be connected are connected to the right wires. Brown is connected to brown, light green to light green and yellow to yellow and dark green to dark green. LIke I said my lights work in every way shape or form except the brake lights. They worked this morning. O well I will try and check for power on the switch and go from there. Thanks for the help hopefully more will come my way.
eric32 said:
Well I have got a hanes manual and all of my wires that need to be connected are connected to the right wires. Brown is connected to brown, light green to light green and yellow to yellow and dark green to dark green. LIke I said my lights work in every way shape or form except the brake lights. They worked this morning. O well I will try and check for power on the switch and go from there. Thanks for the help hopefully more will come my way.
This is actually a common issue with a bad ground. Where do you have the black wires grounded to?

The red wire should be a 12v positive wire that is for trailer accessories such as a winch. The blue wire is a brake controller wire which will not be used unless you have the brake controller. Neither of these two wires will be your issue. Some systems use both the turn signal wire (green or yellow) and the parking light wire (brown) to make a brake light. I would check all the grounds again. Make sure you have a ground from the engine block or battery negative to the frame. Then from the frame to the cab and bed.
Well I will check my ground wires just to see but they are grounded on my frame and I am also going to replace my brake light switch wich only cost's 8 bucks for a new one so it can't hurt to replace it. Thanks guys so much on the wire info and such so I know even better on what I am looking at. I will loosen my ground wires and clean the frame to bare metal again and retighten them.
by any chance,, do you have a trailer plug???aftermarket??a lot of problems start there....'
you stated that your dad rewired rear end,,double check there with a trouble lite.. sounds like you got some wires crossed...
Hello bobjob well the trailer hookup was all taken off and the original wires that are on my tail light bulbs are going to a wire connector with 4 wire hookups. The four colors are yellow, brown, light green, and dark green. There are no other colors and they are all matched up. I still have a brake light on my cab roof top but nothing in the back when I put on my brake. The grounds should be ok cause all of my light are grounded in the same spot. I was thinking about getting a new brake light switch but if it was bad then the roof top light probably would not work but I don't know much about these things. Heck even if I can trace the brown wire clear further down the frame once it goes inside then what? I bought a hanes manual wich has wire diagrams but that does not help much. I don't know really what to do know but man I have to have brake lights. Bulbs are good fuse etc. The lights get power just nothing for brakes.
O yes also bobjob I did check the wires and as far as I can tell they are all hooked up right. The light green ones are hooked up together and both go too the one light green wire on the four wire hookup connector. All the brown wires are hooked up too the brown wire and the yellow wire is hooked up to the white wire hookup and the dark green to the dark green. That is all there is at the 4 wire hookup connector wich is to me something that was not originally there but don't really want to get rid of it and have more wire connections then I need.
ok...everything at rear seems check would be a little harder,,next guess,,assuming that wires to light's are good,,and that you got 3'rd brake light,,i'm guessing,,it is at turn signal switch..or wires coming out of..can't say for sure on your truck,,but if my memory is correct,,brake lite wires go from brake switch -to turn signal switch-comes out and goes to rear lights...could be a bad switch plate... if i'm correct..check your book... :thumbup:
.........hope this helps.,,let me know....
Ok guys here is an update. I replaced my brake light switch and it was not the problem. I checked and I did have power at the brake switch at the brown wire hookup. Now this gets even weirder for me. I checked all my light hookup's in the back and they are all fine and ground is good. Now I traced the whole line of wires clear up to where they plug into the socket under my hood and that socket goes into my firewall and such. Ok now I had a person put the break pedal on and off and I checked the brown wire and it has power and I just happend to check the other wires with the socket and the white wire for some reason is the one that goes on and off when the break pedal is pressed. So I traced the white wire all the way back to the end and I put my test light up to it and it goes on and off as you press the pedal down and off. So now what wire do I hoop it up too? I tried hooking it up to my brown wire and tapping into it but when I put the brake pedal down the back lights does come on but they are just on the same way as when you put your headlights on but they don't get brighter. So I know it can not work with the brown wire. I am at a lost end here. I looked at my 86 s10 under neath it and it has only the same 4 wires gong to all the lights. Dark brown, yellow, light green and dark green.What can I do now? Hope someone can let me know cause I am lost.
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Ok guys here is the last update. I used my tester light and on my old s10 the brake lights go through my dark green and yellow wires wich was stated above by someone. Ok with the white wire I took two aligator clips and hooked it up to the wire connector ends on the yellow and dark green and yes I have brake lights then but how am I going to take that white wire and connect it two the other two wires? Man this is killing me cause I don't want to have to do a bunch of wire connections here. Hope someone can suggest something.Thanks too all you guys you have helped me out a lot so far.
This is the setup for stock GM wiring
left turn & brake lights - yellow
right turn & brake lights - dark green
tail lights - brown
back up lights- light green
ground black (or white)

In most cases you will have a white ground wire for each tail-light, and it will run from the tail-light assembly over to the body. Bad grounds at each tail-light are a very common problem.
When you connected the test light to the dark green wire & yellow wire, and to the white wire, you provided a ground for the light through the test light to the white wire, so the turn signal worked.

I think you have fixed most of the problems, but you need to recheck the ground for each tail-light .

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Does this truck have a module/circuit board in the rear tail light's? If so, this is a major problem I have seen before.
Well I figured out that the brake lighrt is supposed to come through the dark green and yellow wires but at the socket coming out from my fire wall I am not getting power to the dang wires so I am done trying to find out where the lack of power is coming from so I am getting a new signal turn switch to replace the one I have. I should have power again after that. Thanks guys for help.
bad contacts in turn signal switch plate...
Well to answer a few questions asked to me no there is no control module for the back lights just the sockets and the wires. Also the white wire is a hot wire not a ground. The lights already have the two ground wires for each side in the back. The white wire is a brake wire but I am guessing its for hooking up a trailer when you want one to be used. I checked the end of where all the wires go and I am getting no power to the dark green and yellow so I know its coming from inside. I checked my brake light switch and i am getting power to the brown wire and the white wire nothing else. So I will have too put my new turn signal switch on when i get it and check everything while I have it all out. Should find the problem them. I am guessing its the turn signal switch cause I had other issues before and they changed over time with out me doing anything. Thanks guys
turn signal switch bad almost always

when everything works except brake lights

have had this many times over the years

you have good ground if any lights work at all back there

and since you do have other lights your ground is fine
Yeah I hooked up my white wire up to my brown wire so during the day time my lights will power up when I put my brake on and go back off when I let off of it. I will have to be carfull if going during the night but I did no realize that I have been driving like that for over a year now with all these issues. I got a new turn signal switch and this will be my first time putting one in.

I got a hanes maunal and my turn signal switch has three hookups. One has two wires and the other two has many wires. I know one is for the wiper motor relay and I am assuming the other one is for turn signal lights etc. The little one I am not sure. It did not come with any instructions or anything. I will have to buy some special tools to be able to get my dang steering wheel off. Just out of curiousity do you think it can be done in one day? thanks for help
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