Like the title says I'm looking for some help figuring out my instrument panel. I just(tonight) got my truck running again and while driving it around noticed that most of my gauges don't work.

My speedometer works, and it appears my battery works, but my water temp, fuel gauge and oil pressure don't.

My water temp looks like it is going to work but right after I start the truck it runs all the way over to Hot and pegs all the way and stays there. Occasionally it will go to the middle but then it pegs right over to Hot(grounding issue?)

My fuel gauge looks like it is working then goes to empty...I put 20 bucks of fuel in my truck tonight and when I started it at the pump after filling it showed empty but later when I was at my house parking it went over half, then I took it out again and it showed empty again.

My oil pressure doesn't work at all...never has. When I replaced my manifold I took off what I'm guessing was the oil pressure sending unit(just to the right of the distributor on the block) cause I accidently hit the thing and it broke the 45 degree brass fitting. I plugged the hole. The thing is the engine is like a 77-79(I believe) but the cab is a 71. The oil sending unit that was on there was electrical but the gauge is setup for the actual tubing(not sure what to call that). I'm not sure how I can make this work.

Any help with understanding my instrument panel and its gauges would be greatly appreciated. I would really like to be able to keep an eye on my water temp and fuel level;) .

Thanks

mechanical oil pressure guage you can hook up using tubing the metal tubing is the best route but plastic tubing is commonly avaialble at any parts store just need a compression fitting that threads into the block at the hole you blocked off and run to existing line at firewall or to guage if there is no line installed already on guage.
check the temp sending unit wire and that runs along the drivers side head to the temp sending unit make sure it isn,t grounding out somewhere or burnt on the exhuast manifold. disconnect the sender and turn the key on and note guage position now ground the wire and the guage should sweep fully the opposite direction this is basicly testing the guage and wiring, check and make sure it is connected good to the sending unit it may need a new sending unit if the wiring and guage checks ok.
the fuel guage you can test the wiring and guage the same way disconnect the sending unit wire turn on the key note guage and ground wire should sweep guage fully to the opposite direction if checks ok it is either a sending unit problem or poor ground at tank you can use a jumper wire to make sure the tank has a good ground by attaching it to the sending unit or tank and running it to a known good ground.

Thanks man.

I tested the gauges like you said and they both pegged one way when disconnected and the other when ground. So like you said I suppose it is my water temp sender that I need to replace.

Now here is the weird thing about the fuel gauge...the plug was a little loose so when I plugged it back in it worked fine. The weird part is when I turn on my headlights the gauge pegs to empty...the second I turn them off the gauge reads like it should. What's up with that?

should probably check the instrument cluster ground as it may be a poor ground causing some problems there is wiring diagrams posted at the top of the elctrical forum that may be of some help locating and testing the ground.

should probably check the instrument cluster ground as it may be a poor ground causing some problems there is wiring diagrams posted at the top of the elctrical forum that may be of some help locating and testing the ground.

I'll TRY to figure that diagram out :lol: . Which one is the ground?

someone more familiar with the cluster connector and ground location could probably tell you better than I can , on the wiring diagram a ground wire is shown by an arrow made up of lines so any wire that terminate with an arrow is a ground wire you will probably have to enlarge the diagram just to see the arrow.

Ok thanks.

I went out and bought a new water temp sender but wasn't paying attention to the size...the stock sender went into the head with 1/2 threads but I want to put the sender just to the left of the thermostat. Problem is that is threaded 3/8 . There is another place for a sender just to the right of the thermostat and it's 1/2in but I'm not sure if that will be as good of a place.

I used to have my sender in the intake manifold. The problem I had was that the radiator hose kind of crunched into it. I ended up buying a thermostat housing from an early '80s sedan that had a hole in it that the sender fit in perfectly.

The ground for the gauge panel is a black wire that comes out of the back of the gauge panel connector. The wire has a little clip on the end of it that fastens to the back of the metal dash.

Thanks pj!

So how much radiator fluid should I have to drain to put the sensor into the manifold?...I don't want to totally drain it and then find out I only needed to drain just a little bit.

EDIT: Well you were totally right...the hose interferes. I decided just to replace it with the stock one in the head until I get a sender thats 3/8. Problem is the sender that was in there was a 3/8 screwed into a 3/8 to 1/2 adapter...now go ahead and take a guess what I can't get out :cuss: . Stupid adapter is stuck like you wouldn't believe...and it doesn't help that my headers are cramping my workspace. I tell ya if it's not one thing it's another.

Hey R@nger did you ever get you ful gauge problem ? Im having the same prob just cant seem to find the prob, I know it's some mthing real basic but i just cant find it. Any imput or advice would and will be apreciateted.

Thank you

local hardware store should have brass adapters you can use, I had to get an adapter so my oil pressure sending unit would clear the manifold.

Hey R@nger did you ever get you ful gauge problem ? Im having the same prob just cant seem to find the prob, I know it's some mthing real basic but i just cant find it. Any imput or advice would and will be apreciateted.

Thank you

No man, I checked the ground and even sanded both contact points(the clip on the ground and the metal tab it connects to) it still pegs empty when I turn my lights on.

hey ranger have you removed your gauge cluster and looked at how it was hooked up, sounds like some of the stuff isnt hooked up properly or something is shorting somewhere.

hey ranger have you removed your gauge cluster and looked at how it was hooked up, sounds like some of the stuff isnt hooked up properly or something is shorting somewhere.

No I haven't...is it a pain to take out?

Not sure :(

did you guys figure this stuff out, im going throught the same probs now

did you guys figure this stuff out, im going throught the same probs now

Nope, I still haven't figured it out...of course I haven't really worked on it much since I last posted so ya :lol: . I just don't have the time to pull out the whole instrument panel to see what's going on. I suppose I'll fix it one of these days.