Aaron Johnson

my brake lights and turn signals dont work i just got the 99 jeep grand cherokee today and i found out the problem the harness that comes from the multiswitch some of the wires are cut and burnt and the brake switch isnt hooked up either does anyone know or had to rewire theirs?
blinkers and tail lights and backup lights dont work but headlights and hazards do need help asap or at least a wiring diagram.

thanks in advance

dave1123

The best I can offer you is a Full Service Manual from pacificcoastmanuals.com The one for my 2000 has about 20 pages of wiring diagrams that are involved with your problem. I was going to print one out, but there are too many circuits included in that multi-function switch for me to do that.

The FSM is about 93mbs of pdf files you can download for $7.99 specifically for your year. It covers just about every thing on your jeep. Troubleshooting, testing, even diagnosis and component locations.

Cherryokee

This is what I found and repaired when I discovered almost similar trouble in my '99 XJ. The connector/harness that mated to the switch had melted due to electrical overstress caused by mis-mated contacts. I say mis-mated because when the two were connected at the factory, a few pins did not insert to their corresponding receptacles but slipped into their cavities, between the cavity wall and side of receptacle. The poor connections would heat, melt plastic and make the cavity larger, thus connections would become more intermittent over time and lead to more heating....get the picture? This had been happening over a seven year period before it showed-up as a problem (except that the hot-melty smell started a couple years before that).

Keith333

I had a oil pressure sensor wire go bad on me a few years ago. The gauge would drop to zero when warmed up and coming to idle (red light, etc.). I've said that to say this - my local NAPA dealer had the connector and harness in stock for under $20 and that took care of the problem. I have no idea what your wiring situation looks like but someone may stock what you need to replace. Best wishes either way.

Aaron Johnson

i can post a pic from what i can tell someone rigged only the taillights to work but the wires burnt and im not sure if the turn signals tie into the brake switch it doesnt have the connector only the two wires someone rigged

Aaron Johnson

ok keep in mind its a 99 jeep grand cherokee but heres a pic of the wires i have half of each one was burnt but i believe their for the brake lights turn signals and backup lamps

this iod connector theres a white with red stripe wire and one that doesnt have a wire cause it was burnt


this pic everything i look up the colors dont match but its the only loose wires that were there which are these colors
blue w/ orange strip
grey
green w/ orange strip
i think its white with a red strip

Aaron Johnson

i need to know if the brake switch connector is on the in dash wiring harness or the behind the dash wiring harness. i assum the in dash because thats the one that has the multswitch on it but idk if someone could shed some light itd be much appreciated.
thanks in advance

Cherryokee

This should help with identifying wire colors. I think I see a Dark Blue with Red 22AWG and Orange with Dark Green 22AWG (for Speed Control power supply - probably from pins 3 and/or 4 of brake lamp switch conn.) along with a White with Pink 18AWG and a Black 18AWG (for Brake Switch sense - from pins 1 and 2 of switch conn.).

Are you doing all this by eye-ball, using an ohmmeter or other electrical measurement/indicator devices? Do you have your tail light connectors unplugged/exposed for testing? I was able to identify the wires when I compared your picture of loose wires to the wiring diagram. BTW: The brake lamp switch is mounted to the brake pedal arm and the connector should be either connected or stowed near-by.

Follow the wires from the connector to the harness...

Cherryokee

Aaron, Please do yourself a huge favor. You really need to do this if you want to delve much deeper because it gets harder and harder to describe, or make sense of, this kind of work without being hands-on. Break down, follow Dave1123's advice and buy the FSM from pacificcoastmanuals.com. You just can't go wrong for under $10, having this reference is an education all by itself plus it will save you thousands of dollars.

Aaron Johnson

ok will do, i got it figured out though went and got half the harness from the junkyard and got it all wired up, only thing those theres 2 orange wires, 2 pink w blk stripe and 2 grey w red stripe and they all look the same are these just power wires to different things cause the 2 floor lights both have an orange wire so thats what i figured. im about to test if it all works wish me luck.

Aaron Johnson

everything now works yay, thanks cherryokee went with your idea and rewired it with a new harness and worked flawlessly now i gotta figure out with the driver seat buttons dont work and driver passenger window
and it turns out it was fuse 20 for the turn signals it was blown