No speedo, brake and ABS lights on

[Udaloy]

Three days ago I changed the clock forward one hour. Two days ago, I noticed that the clock was off by 2. 5 hours when I went to lunch. Last night I installed a set of KC lights, and on my first trip out I had no speedometer, parking brake light and ABS light's are on.



I went out this morning and noticed one of the nuts on the positive battery post wasn't tight, so fixed that. No difference. I ran the actuator test, but didn't receive any numbers like I've seen posted elsewhere. I received the following:



C-CODE

21 18

A4 38

A7 67

AA 67

AC 00

00 00



The lights are on a simple rocker switch setup with a relay, not run with the headlights in any way (the KC's are located in my rear bumper). We're grounded to the negative post of the battery and we're drawing power straight from the battery as well. I don't see how adding the lights would make this happen, but I don't believe in coincidences. I'll go see if I'm getting any error codes and post what I find as well. Any help appreciated.

 

[Udaloy]

I didn't have any Diagnostic Trouble Codes read by the Bully Dog and I didn't see any when using the key on/off method. It just said "done".

 

[B.G. Smith]

The speedo and the ABS system both receive input from the sensor mounted in the top of the rear differential. Could be a loose connection there? bg

 

[Udaloy]

I'll go look, thanks.

 

[Udaloy]

All connections are fine at the rear axle. We weren't near there during our install either, so that makes sense. I checked my fuses and found none blown. I only see two applicable: #6 - 40A ABS Pump and #35 - 10A ABS Module.



Is there a way to test the speed sensor in the rear axle?

 

[B.G. Smith]

The sensor is a wound coil I believe, with it unplugged you could check across the terminals with an ohm meter and should get a resistance reading but I don't know what the reading should be. I believe the signal from that sensor goes to the PCM and the PCM sends signal to speedo? Could you have disturbed the connections at the PCM? It is mounted under the hood, probably on the firewall somewhere. bg

 

[Udaloy]

Ok, it's taken me a week to post, but here's what was wrong: the ground bolt was not tight. It's located under the hood on the driver side, right above the ABS computer. My buddy was looking for a place to mount the relay and forgot to tighten the bolt back down after deciding to use another bolt. Figured I better post for the next guy that runs into it.