Rear antilock brake light

[robmoore11]

I am starting to think that the reason my speedo is out is because the rear antilock light is on. It's been on quite some time but my speedo fluctuates between being accurate and being out up to 15km/h. But I started noticing that when it came on is when I felt like I was driving to slow in traffic. How do the speedos on these trucks work? I thought it was through a cable not a sensor in the axle :S

 

[gdhillon]

Mine is a 93 and the sensor on rear is also the abs sensor. So when I had no speedo I had my abs light on. my issue was one of the wires pulled apart (had a nice duct tape patch job)

 

[Shadetreemechanic]

You are right around the transition year so I am not sure what you have. My 88 had a cable, but the 92 used the speed sensor in the rear end. Take a look at your rear chunk for a sensor on top. that would be your speed sensor.

 

[trackspeeder]

1990 uses a cable. You will find it on the left rear of the tranny.

RABS sensor is on the rear end.

 

[robmoore11]

1990 uses a cable. You will find it on the left rear of the tranny.

RABS sensor is on the rear end.

Thanks for all the posts guys. And I was under the impression that the speedo read how fast the rear tires were moving? Not the Trans :S but I am going to have a look tonight at the rear axle again, I tried getting that plug off the sensor the other day but did not want to break anything so I left it be. Going to spray a little lube on it to try and crack it loose maybe today.

 

[robmoore11]

And I checked the wiring I cannot see any problems with it. Should I maybe change the sensor while I have it out checking it? I know for sure it hasn't been changed in at least 8 years. If so do you guys have the napa part number?

 

[Slade]

I had the same issue on my '94 and it was just the sender in the rear. I don't know the part number but there is more than one so take the old one with you.