Hey everyone. New to this site..and trucks. This is my first truck and there are a few problems but I'll just start with the gauges. I have an 89 straight 6 auto. Just got it in September. I have only been using my rear tank because the fill hose to the front is cut. My gauge for the rear tank is stuck on empty. My temp gauge also doesn't work. All my fuses are good. I haven't dropped the tank yet. Is it just a coincidence that both lower gauges on my dash aren't working? What should I check? Thanks in advance.

 

For the temp gauge, it's possible it could be the temp sending unit on top of the engine.

One way to check is to unplug the wire from the top of the sending unit, and ground it somewhere on the engine block. Then have someone inside the truck watch to see if the gauge moves. If the needle goes up when you ground the wire, then change the sending unit. If the needle does not move then the problem is either in the wiring, or the gauge itself is bad.

 

Fuses are good?
How about the oil pressure gauge?
If all three are out it might the ICVR.

 

Yep fuses all good. Oil pressure gauge good too. My front tank reads all the way full. But the guy I bought the truck from has the tank selector (on the rail) mickey moused, bypassed and capped off for some reason. Not sure it has anything to do with the problem, but doesn't look good

 

Not good !

 

Do u think this being bypassed would have anything to do with my fuel gauge not working?

 

Yes indeed !

 

I would replace the part or just run off one tank.
The filler hose should only be like 25.00 or 5.00 at a jy.
I heard the selector valve might be 80.00?
Just a guess.
Fix the broken stuff first and I bet the other problems might go away too...