ABS and Brake lite stuck on

[Royal Squire]

Beginning yesterday my abs and brake light in inst cluster are stuck on. Fuses are good. Is the problem still more than likely the speed sensor on rear axle, even if speedometer was working most of the time until late today when it seems to have quit completely. Any input on this would be greatly appreciated. 

[Me78569]

Use a paper clip to "jump" the connection/plug on the rear pumpkin then use a multimeter under the hood on those wires to verify that the wiring is good.  If it is then replace the sensor.

[Royal Squire]

Will do. Thank you

[Me78569]

if you see the resistance in that circuit as high I would first look at the junction above the drivers front tire.  all of the wiring for the bed of the truck goes through it and it can collect a lot of dirty / salt.

[Mopar1973Man]

Also while the sensor is out to check the tone wheel for placement. One of members had a similar problem had a bearing fail in the differential and the tone ring shifted out of view of the sensor.

Be aware the sensor most likely will not come out without breaking. Make sure to spray plenty of PB blaster or WD-40 to help it but if the crude and mud is pack down there the o-ring will hang up. So carefully pry little pieces and break the off till you get the sensor body out. Been there, done that...

[Royal Squire]

Sounds like fun 

[Mopar1973Man]

Will give out the other secret there is no way to access the sensor from inside the differential unless you remove the carrier with the ring gear. So if you careful you can still do all this without opening the differential.

[Royal Squire]

Could not find a break in wire, checked plug at left front wheel and was clean as a whistle. So I decided to replace rear speed sensor. Got it out in one piece, used more patience than I'm used to. Struggled to get new sensor back in. Keep in mind it's been a couple weeks since I tried to find break in wire. Guess what I found after I had the sensor all installed 

[CTcummins24V]

Tree rats were at it again

[Royal Squire]

Never thought of that!! Need to set some traps. How big are tree rats? Maybe I could just electrify the whole truck and if any critters touch it....ZAP! Already had mice make a home in hood insulation. 

Maybe I'll just concentrate on repairing wires 

[Mopar1973Man]

Really come issue out here in Idaho. Pack Rats will do the same thing if you don't rid of them quickly. One reason I stopped plugging the truck in. It made perfect habitat for rats and mice to hang out at night. "Ohh I'm bored. Nice wiring loom to chew on..." Munch, munch, munch...

[Me78569]

That's why I always test wires for resistance now if I have an issue like this.  It is VERY easy to miss a busted wire.

[Royal Squire]

Was pretty sure I had a broken wire, just couldn't find it. Was afraid it was up in the frame behind fuel tank.  No critters involved in this break, conduit is brittle an have had a lot of ice and mud hanging underneath this winter  

 

[Royal Squire]

Nice to have speedometer and cruise working again and no lights on inst cluster. 

Wasnt an issue on this repair, but what is the best way to clean corroded or dirty wire, like a broken tail light wire so it can be soldered. Thanks as always for all the help. 

[CSM]

Normally I cut out the bad section and replace it.   Good waterproof heat shrink is used to cover the joints.

[Royal Squire]

Sometimes you can cut out quite a bit and copper is still kinda black. 

[Me78569]

Yea, nature of the beast,  I have cut large sections of wire out of my truck and replaced it with new stuff.

[Royal Squire]

Haven't found any on this one but I have on other vehicles. I have cleaned and made a pretty good solder joint on some bu not easy. 

[Buzzinhalfdozen]

I've used electrical contact cleaner and a fine wire brush as a "temporary" fix and it works ok. Still frustrating to solder though. 

[dripley]

Just to throw this out there, the other day I noticed that my abs, brake light and air bag light was lit and no speedo. I have been having some issues with the switch being stiff lately and noticed I could remove the key after starting while the engine was running. i stopped and restarted the truck and thats when I noticed the switch was not returning all the way after releasing it so the next time it happened I manually returned the switch and the lights went out immediately. While I see yours is a wiring issue mine seems to be a worn out switch and key. 14+years on the one key has taken its toll. I started using my spare key which is new and and the issue seems to be gone now.