wiring / ABS question - trouble codes

[MyNewSy005]

so my ABS light has been on since I got the truck. and I threw parts at it before i really checked it out i.e. new ABS unit, etc. so i finally broke the scan tool out and looked into it.

3 codes popped up:

65 Open Relay Circuit
66 Shorted Relay Circuit
86 Shorted Antilock Warning Lamp.

The 1991 RWAL/4WAL guide says to fix any other code before 65/66.

Checked circuit 852 (white wire) at the ABS unit. have 11 volts. checked gain at the fuse block. 11 volts. so i finally took off my gauge cluster and tested the terminal. 0 volts.

so am i correct in saying there is a short between the fuse block and the cluster, deep inside the main harness?

I am testing everything with the ignition ON, truck not running.

Am i right in thinking its not a ground issue because all the other gauges/lights in my cluster work fine.

AM i missing anything?

If i ran a fresh wire from the fuse block and spliced it into the circuit at the gauge cluster connection would that theoretically solve my issue?

I am working under the assumption that with the igniton on the 852 circuit should show some volts where it connect to the cluster.

any and all thoughts appreciated.

thanks

 

[sly dvl]

Re: wiring / ABS question - trouble codes

There might be an easy common fix for this issue, but I'm not aware of it. After checking my schematic it would appear that circuit 852 (gra/wht) should be the ground side of the ABS warning light. But you checked the fuse box? My schematic doesn't show it going anywhere near the fuse block.
I'm going to shut up until someone with another schematic chimes in to verify the correct wiring. :lol:

Are you testing this with the cluster removed?

 

[MyNewSy005]

Re: wiring / ABS question - trouble codes

Well I checked the volts at the fuse block @ the brake fuse, at the junction block from the engine side.

i worked backwards from the ABS unit toward the gauge cluster.

i am testing the 852 circuit at the cluster with with gauges removed.

i am not great with electrical so i could have overlooked something. i guess the real question is if the harness that conects to the gauge- should it show voltage with the ignition on or does the cluster need to be installed.

thanks everyone for looking

 

[MyNewSy005]

Re: wiring / ABS question - trouble codes

Thank you dave. That sheds some light on the issue. So I should be looking for a ground issue?

yes i did replace the BPMV with a reman unit. will start looking at ground issues and report back. is there a way of totally clearing the codes and starting from scratch? because my genisys scan tool wont clear any of the codes, not even the 86. even with the battery disconnected for a hour the same three codes are still present.

thank you everyone for looking.

 

[Davemc1963]

Re: wiring / ABS question - trouble codes

What software do you need (is available . besides a Tech1) to check for ABS trouble codes? I have Diacom+ but I didn't think that will check them. Or is it just a matter of using the paper clip in the ADSL and counting flashes? Anyone got any info on this? Thanks

 

[MyNewSy005]

Re: wiring / ABS question - trouble codes

Big thanks to everyone for all their help, esp Dave.

I reset using the aldl trick the BPMV cycled and my ABS light is off.

Months ago i found the BPMV 2 way connecter power and ground wires by the battery dissolved by what looked tgo be battery acid. so I fixed them up and expected the ABS to clear itself. and then I used my OTC Genisys scan tool to try and clear them with no luck.

So i have been driving around for 6 months thinking there are more things wrong with the ABS, even though i had been getting the same 3 codes.

Turns out I had already fixed he problem but thanks to Dave's insight i learned the codes dont reset unless you jump the ALDL connector. I dont know if a Tech 1 will reset them but i now know my Genisys wont, even when it gives me the option.

this will be the 1st time in the 2 years i have owned 005 that I will drive around with no ABS light on!!

this is a great community and cant thank all of you enough for the support, help and knowledge.

 

[sly dvl]

Re: wiring / ABS question - trouble codes

Another satisfied customer of SyTy.net :tup: