1989 speed sensor and instrument cluster

[1989k2500]

So the good news is that the sender in the transfer case is good. Gauge still goes out when headlights are on. I found that out after spending $85 bucks on a new sendering unit

PS I joined this gmt400 forum because that's obviously the type of vehicle I have.
So im not sure why anyone would think its some carry over square body

 

[1989k2500]

I don't get why the speedo only goes out when the headlights are on. I put another ground from the back of the cluster to the frame. That didn't help anything.

 

[1989k2500]

I can't believe that with all these teucks out there mine is the only one with these symptoms.
I would have thought that there are plenty of people not just knowing whats up, but also know how to fix it

 

[Mark Gilbert]

Talking **** is a great way of getting people to help.

For someone that can't figure it out on you're own you have a lot of nerve complaining that others can't fix it for you...

 

[Wrench]

Just caught the last few posts.

If your gauge cluster goes whack when you put the headlights on than you've got current crossing overr. That's logical right.

2 things like would do first.
Try a different dash cluster. Swap one put with the a buddy for testing purposes.
If the issue persists unplug the dash lights from the lift switch. Maybe a dash light is shorting on the board.

Lotta typos. I'm not correcting them.

 

[1989k2500]

Changing the cluster mught be difficult. They only made them from 89 to 91 with my wiring. I am looking a bit closer at your suggestions

 

[evilunclegrimace]

I don't get why the speedo only goes out when the headlights are on. I put another ground from the back of the cluster to the frame. That didn't help anything.

Unplug the rheostat for the dash lights and see if the Speedo still acts up when you turn on the headlights.

 

[1989k2500]

I think I got it tracked down to the headlight switch and dimmer. Took the dimmer switch apart and cleaned it. The headlight switch had some corrosion going on . Ill replace them both if i have to

 

[1989k2500]

I did a few things yesterday, So I am not sure what did it:
-removed the solder and desoldered all pin connections on the cluster.
-ultrasonic cleaned the cluster board
- disassembled and cleaned the dimmer rheostat
- disassembled and cleaned the light switch , but then decided to just buy a new one.

So if you have similar or the same issues with your gauge going out while the headlights are on. then don't right away waste money on a new speed sensor.
Clean the connections first and replace the dimmer and light switch first.

 

[PlayingWithTBI]

Congrats