Cluster Replacement Questions for 88 C3500

[ewodarz]

I have a cluster for my 88 C3500 with a non-working odometer and gas gauge. I've been looking at ebay and local salvage yards for a replacement.

I don't want to get a new cluster as I mostly use it for dump runs or going fishing. I don't want to drop 1K in it.

I see that I can get a rebuilt cluster "pro-rebuild" for 350 OBO. Other salvage yard clusters range from $150 to $225. I'm tempted to go with a rebuilt cluster. Hopefully that makes sense?

Also, I understand that the matching of clusters is difficult based on gearing and other factors. I have a 5.7L with an 8 foot bed.

Any help would be appreciated.

Thank you!

 

[someotherguy]

"Direct" replacement cluster must come from a 1988-1990; 1991 can be made to work but you'll be re-pinning 3 wires in the connector.

The reason I put "direct" in quotes is because the speedometer calibration is done internally on 1988-1991 clusters, and the likelihood of getting another one that is set correctly by coincidence, is pretty low. Initial calibration is based on your original equipment tire size and axle ratio; you can change this to fit any modifications you've made in this department. I did a write-up on it where you can install a simple DIP switch instead of the silly "programming clip" method GM devised, and the DIP switch can be changed infinitely of course. Write-up is here -> https://www.gmt400.com/threads/recalibrating-1988-1991-speedometer-dash-cluster.62022/

BUT..

The only 2 issues are odometer and gas gauge? Do you really want to spend $350 on a replacement cluster for that, on a truck used for dump runs and fishing? The odometer being broken is pretty common on 1988-1991 clusters. Gas gauge is probably the sending unit in the tank or the wiring between them; the gauge itself rarely goes bad.

Richard

 

[ewodarz]

"Direct" replacement cluster must come from a 1988-1990; 1991 can be made to work but you'll be re-pinning 3 wires in the connector.

The reason I put "direct" in quotes is because the speedometer calibration is done internally on 1988-1991 clusters, and the likelihood of getting another one that is set correctly by coincidence, is pretty low. Initial calibration is based on your original equipment tire size and axle ratio; you can change this to fit any modifications you've made in this department. I did a write-up on it where you can install a simple DIP switch instead of the silly "programming clip" method GM devised, and the DIP switch can be changed infinitely of course. Write-up is here -> https://www.gmt400.com/threads/recalibrating-1988-1991-speedometer-dash-cluster.62022/

BUT..

The only 2 issues are odometer and gas gauge? Do you really want to spend $350 on a replacement cluster for that, on a truck used for dump runs and fishing? The odometer being broken is pretty common on 1988-1991 clusters. Gas gauge is probably the sending unit in the tank or the wiring between them; the gauge itself rarely goes bad.

Richard

Thanks Richard. I saw that post (which is awesome ) and while I have a soldering gun, I doubts whether I am worthy of that sort of effort.

I'm a bit on the fence as to put money into the c3500 or buy something a little less long in the tooth.

I wanted the odo to closely monitor gas mileage, but I did a little dead reckoning on the freeway with mile markers and came up with 12.9 mpg. Which is surprisingly good considering there's an 8'x4'x3/4" steel plate welded to the truck bed.

The steering was a little squirrelly, but I'll have someone work on that.

Thanks again Richard.
Erick