1998 Chevy 3500 Diesel Wiring Diagram
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Before clipping any wires, keep in mind that most older model year trucks have the same bulb filament used for both the brake function and the turn indicator function. For that to work, the brake wire runs to the turn indicator, so that when you turn on the flashing turn signal, it switches out the brake light signal for that side so that the two signals don't collide. So don't just check the brake light. Also check the turn signals. In my case, the brake lights didn't work but the turn signals did, so that told me the wiring to the bulbs was OK and the wiring running in the frame was OK and the bulb contacts were OK. So I assume I need to check the brake light switch, the fuse, and for a truck, any wiring done for the trailer hitch to make sure it is OK.
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I had the same problem on my 91 K1500. The most common reason rear lights of any kind will fail is rotted wires. They run through wire shroud from front to back along the inside of the frame to the left tail light. Running this way leaves them exposed to the elements.
Check along the run for rotted, broken or degraded wire. Most spots would be at anchor points, junctions, etc. If you do find a faulty wire, just run a new one from the engine bay to the back and splice it in. Its a cheap fix and takes WAY less time.
If it was me i would clip the wire at the tail light harness, about 4 inches back, then move to the engine bay and look for the same wire there. it will most likely be beside your brake fluid assembly, in a cluster, entering the firewall. Find the wire and clip it about 4 inches back too. Solder and shrink tube the new wire to these pigtails and give it a test.
If you are unsure of the wire color associated with brake light function, you can access wiring diagrams online, but be warned, chev/gm have been known to change color codes from time to time.
It could also be a relay, the box is located in the engine bay and the relay will be marked, but its unlikely to be the problem.
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There is a switch. I think on most C/K 1500/2500 it is on the brake pedal arm or the arm hits it. It is $5-$10; you might take ALL your truck data to the auto parts store, buy a new switch, then look for the same thing around the brake arm or under the hood.
There's a fuse. Find the fusebox and look for "brake". The Owner's Manual may have clues.
Fuses usually blow for a reason. Some bulb-faults can blow a fuse. Change the brake lamp bulbs; on a vehicle this old it is time to do that. Open tailgate, there's two (rusted) Phillips screws into the taillight lens. Unscrew, the lens un-hooks on the other side. Flat rubbery thing with connector and 3 lumps. Unhook connector latch and carefully pull out. Use 1/4 nutdriver to remove 2 screws in rubbery thing. Three bulbs: they just pull out but won't want to come easy. IIRC bottom is backup and the top one is brake.
Look at the wires, because if it is not switch and not a bulb-fault, then as TBAS says it is probably wires, pinched or broken, from tail to switch to fusebox.
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Turn your flashers on to check the bulbs .Checks good go to your brake light switch mounted on upper part of the brake pedal with a simple test light you should have hot (test light on) when the brake pedal is depressed if not and the ong wire is hot (15 amp fuse in the fuse panel under dash) says STOP by it you need to replace the brake light switch. Also when you replace the battery get the highest cranking amp one that Will fit.
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Woods
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I had the same problem with my stepside cleaned the connections at the light and they went to working
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Nikolai
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like others were saying its a brake switch at the top of the brake pedal. just did mine and it was a pain but it solved the problem instantly. just need to remove a clip and lift up on the plastic piece to remove it from the brake cable, then disconnect the wiring harness and pop in the new one, atacth the clip and you are good to go.
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I have a 1994 GMC Sierra C1500 2WD with 4.3l w/automatic. It was a fleet vehicle. Plain Jane accept for High Output Heater, Limited Slip Diff and Engine Block Heater. Brake lights were working intermittently. Would come on when pedal as first depressed then go out after pedal traveled down a bit. I put in a new switch and all was well for 3 months. Then the problem came back again. I was ready to put a new switch in again when I took a close look at the wire connector on the harness. The end yellow lead was melted in the connector and the female plug for this wire was black. I got a boneyard replacement and wired it in. Problem solved.
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Been reading about all your various symptoms. I have been fighting a taillight issue for 2 days. Only left turn worked -- No brake lights -- no running rear lights -- no flashers -- no backup lights. But driver side turn sig DID work. Changed all bulbs (were ONLY 25 yrs old) -- Ck'd bulb sockets (all ok) Ck'd fuses and pedal switch - both ok. Charted all progressive actions. Nothing made sense.
THEN thought back on what I might have caused when I took the bed off to replace a brake line in Sept. -- traced all movements I might have made that might've CAUSED the taillight issues. Looked the wire connections over and came to a ground at the frame near the trailer hitch lead. Took it loose - did a fair job cleaning the frame surface rust and reconnected it. Thought I had done a thourough job but still no change. Went back to that ground again -- took it loose -- stripped the wire casing back a couple inches and BINGO!!!!!!!! The wire was rotten ------------ Stripped the wire casing back real good
and got to good clean un-rotten wire -- took a FILE to the frame rail rust 'till I found bare metal re-attached the ground VERY WELL ------------no more taillight problems. So if things get just too wierd - ck your grounds!
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It is probably your fuse relay swithch underneath the hood toward the driver side. Pull the plastic cap off the fuse chassis and you'll see a square relay fuse switch and replace it for the brakes. It's only $13 bucks and is the predominant issue with 1997 Chevy Trucks and the brakes not working especially if you reverse and blinker lights do work.
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Its the taillight circuit board or a broken wire. If you look on here i asked same question and i posted up what the reason for my issue ended up being. Moat likely a bad or broken ground, circuit board that is on the back of the taillight or a broken wire. To figure it out get a test light clean a piece of metal connect teat light ground, then unplug taillight and stick trat light probe into 1 slot at a time see what works and what doesnt and write it down. Then go to the other taillight do samething.
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Either you have a broken wire, or blown fuse or you have a messed up blinker switch. The way those taillights work theres a white wire under dash on the column that white wire is for brake light. So the way the brake lights work they go through a relay and through blinker switch. So you could have a blown relay i would start there. 1 relay is on the back of the fuse panel, the other is next brake pedal on that panel to the left of the brake pedal. Try replacing those, and if that doesnt work look for broken wires under dash, and check all the fuses, replace blinker switch, and hazard switch. If all that doesnt fix it then you must have broken wires or bad grounds
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You may need new circuit boards. If you pull the brake light out an it is burnt that is why. Check the fuse before.
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White wire off the brake switch and also with the cluster of wires front front to back is the brake wire that turns on the brake lights i just figured it out on my 92 chevy k1500 because i have the same issue and i need a inspection sticker
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Check your grounds?
I have brake lights and turn signals when I pulled my "tail light/ courtesy marker light" fuse
But when I put the fuse back in I have no turn signals and my brake lights don't work.
So I guess it could be whatever ground for the running lights could be shorting something out?
Possibly the circuitboards to the brakelights?
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Are the bulbs good or blown. It could be a blown fuse or a problem like mine had which is the passenger tail light wire was pinched/smashed.
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Awesome!!!! it worked for me on a 1997 k2500. Cables were pulled too tight. Once i combed back the cables the brake light started to work.
Thanks
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Hello fellas and thank you for your forum. I came to this site when I had the same issue with no brake lights after changing a booster. After many days probably a full week of taking it apart put it back together I figured out the problem was the hole at the end of the shaft that slides onto the brake pedal with the switch is therefore I drilled the hole of slightly larger and that fix my problem I went to the auto parts store and look up the parts numbers and they are definitely different numbers
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Have you checked bulbs? I'v got everything working now from replacing bulbs except reverse lights are still out
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I had this same problem. When I bought it from the first owner he told me someone tried to steal the car and hot wire it. When they were in the process of doing so they broke the hazard light switch on the steering wheel. I couldnt figure out why my light didn't work. After a lot of trial and error and research I pulled a used switch from pick n pull and swapped it out. Problem solved. I'm a carpenter and not a mechanic and some how figures it out on my own. Google and YouTube can be very helpful sometimes.
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1993 K3500, same problem...no brake lights but had all other lights. I found the white wire coming from the turn signal harness broke down at the flat connector at the bottom of the steering column. r2'd the harness and now I have brake lights!!!
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I had the same break light problem. After changing pedal switch and tracing all wires making sure of no bad wires or loose grounds still no break lights,accidentally found out the problem was "MY BULBS WERE NOT MAKING SOLID CONNECTION INSIDE THE SOCKET" cleaned all the bulb receiving sockets with a light solvent and used a straight pin to slightly pry my bulb leads out just a very little. Problem solved!!
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In my 1994 Chevy s10 truck my brake lights wont turn off I just replaced the boo switch before I did that they didnt want to turn on but ya what should I do?
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Chased no break lights but high mount was working along with all other lights worked fine turned out to be bad conection on combination switch plug
Im ashamed to say it took 5 hrs and im not a rookie i did unplugged and check previously but it was the conector retainer wasnt alowing enough hold for proper connection
1995 chevy suburban k1500 k398miles
(Really i think its time to take her to a gambler500
But shes never left me stranded other than #10boltssuck)
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I have no brake lights, reverse lights or running lights on my blazer. I've replaced fuse, checked bulbs, replaced brake light switch, checked wiring under dash and along frame rail with no results! I did however fix the gas gauge.
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Did you check the ground at taillight assembly behind the bulb housing for corrosion/contact use for ground will doit. Sometimes it's stupid simple things you wouldn't normally think of
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I have a 1993 Chevy k1500 I have no running lights in the rear the brake light works and the turn signal works to but no running light what could be the problem
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Was just helping my Father-in-law work on his '92 C1500. Had no brake lights and hazards were not working. The "STOP" fuse was blowing - sometimes after the brake was activated, and sometimes as soon as plugging in a new fuse. In trying to remove the fuse panel to check on wiring connections on the back we discovered that the hazard flasher (makes the ticking noise when the hazards are on) was broken and shorted out. We took the flasher out and the brake lights work great. Put the flasher back in and the hazards came on immediately but stayed on. The clear case around the flasher had broken and the copper was resting on some other ground point. I think it shorted the circuitry inside. So, off to the store to get a flasher. Glad we didn't tear all the wiring out of the truck like we talked about doing.
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I guess I'm luckier than most…got more than one Chevy…..I have a c3500 with brake light issues…I tried the lights on another vehicle and they are fine…new brake switch…fuses are fine….gotta be a ground wire…changing the brake switch is a pain when I had to drop the steering wheel…figure I might as well change the lights on the cab…was shocked when I found no bulbs in it to start
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I changed my brake light switch and my brake lights don't work i can activate the brake light switch by pressing the little tab but its all together it dont work all my other lights work its a 1997 chevy suburban
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I'm not quite done yet I didn't have any lights no I just got brake lights to fix yet. I got then working under the dash when hit the pedal coming out of the switch I'm thinking it's probably the relay it doesn't click when power is applied to it either that or it's in the column in the single light switch, but anyway don't forget the ground underneath the dash right behind where the OBD1 connector is that fixed most of my issues right there it didnt look bad a little bit of blue between the dash in the connector could be seen when I took it apart but by looking I would have thought it was a good connection
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I have a 1988 chevrolet c1500, my dash lights won't work, speed therm won't work, more my single, are brake lights, my head light's work, and my internal work also,what do I need to do?
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Source: https://www.ifixit.com/Answers/View/32226/Why+dont+my+brake+lights+work
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