Author Topic: Help on gauges! (Read 3001 times)

Slolyfe · « **on:** Jan 20, 2012, 10:28:03 AM »

So I got an 82 with a 22r. After a hard nose over flop, my fuel and temp gauges stopped working. All the obvious wires are still intact, but I have not looked behind the dash.

Do they share a ground? All other gauges are working fine. Any insight would be great. Thanks!

BLACKDOG · « **Reply #1 on:** Jan 20, 2012, 12:05:00 PM »

Fuses ok? sounds dumb, but when I laid my truck on my side, I lost my rear lights. Somehow the fuse popped out.

fordh8r · « **Reply #2 on:** Jan 20, 2012, 04:26:25 PM »

Have you done the troubleshooting and shorted out the wire at the sending unit? The only thing to do from there is get behind the dash and start checking for an open circuit in the wiring and whether or not you have the correct voltages or ground and if all that checks out ok...it's the gauge.

I'm guessing it will be the gauge if all your other gauges are working.

Slolyfe · « **Reply #3 on:** Jan 20, 2012, 06:50:41 PM »

So far just checking the temp gauge.
I replaced the sending unit and it has correct resistance for the temp it is running.
All the fuses are good.
Checked continuity between the back of the dash and sending unit. Its good.
Checked the dash gauge per FSM and it is at 25 OHMs, which is correct.

WTF!?!?

Just to be sure the Temp sending unit is the plug screwed into the pass side of the head. In between the fuel pump and intake manifold. Correct? That is the one I have had come disconnected in the past and I lost temp gauge.

Thanks men!!!

Slolyfe · « **Reply #4 on:** Jan 20, 2012, 06:53:13 PM »

Quote from: fordh8r on Jan 20, 2012, 04:26:25 PM

Have you done the troubleshooting and shorted out the wire at the sending unit? The only thing to do from there is get behind the dash and start checking for an open circuit in the wiring and whether or not you have the correct voltages or ground and if all that checks out ok...it's the gauge.

I'm guessing it will be the gauge if all your other gauges are working.

No fuel or temp. Have not looked at the fuel float yet.

fordh8r · « **Reply #5 on:** Jan 20, 2012, 07:01:48 PM »

Well, if you want to be sure about the wire being correct for the gauge, all you have to do is short it to ground and it should make the gauge sweep to full hot. If it does then you have the correct wire and you just tested the gauge circuit all at the same time.

Slolyfe · « **Reply #6 on:** Jan 20, 2012, 08:19:10 PM »

Quote from: fordh8r on Jan 20, 2012, 07:01:48 PM

Well, if you want to be sure about the wire being correct for the gauge, all you have to do is short it to ground and it should make the gauge sweep to full hot. If it does then you have the correct wire and you just tested the gauge circuit all at the same time.

Ok, I shorted them to the positive of the battery and both went to full.

So what does this mean? Where is the problem?

Also pulled the fuel sending unit/float out, and its resistance increases and decreases with movement of the float.

fordh8r · « **Reply #7 on:** Jan 20, 2012, 08:50:21 PM »

You're supposed to short them to ground not positive.

fordh8r · « **Reply #8 on:** Jan 20, 2012, 08:52:17 PM »

I forgot to mention, turn the key on first then ground the wire. The gauge should sweep to full if it is working. If it is working then the sending unit is no good.

Slolyfe · « **Reply #9 on:** Jan 20, 2012, 09:08:30 PM »

Quote from: fordh8r on Jan 20, 2012, 08:52:17 PM

I forgot to mention, turn the key on first then ground the wire. The gauge should sweep to full if it is working. If it is working then the sending unit is no good.

Ok, with the ignition on, ran a wire from the negative on the battery. to the wire off the temp sending unit. Nothing happened. Did the same to the wire from the fuel sending unit. Nothing happened.

THANKS A TON!!!! for dealing with my electrical retardedness!

fordh8r · « **Reply #10 on:** Jan 20, 2012, 09:17:34 PM »

No problem, Bro! Glad to help whatever I can!

Now you need to access the back of the dash and see if you're getting ignition voltage to the gauges and also check for them having a good ground. Double check the connector from the harness to be sure it's making good contact.

Worse case scenario, you could always bring it to me and we can check it out.

Slolyfe · « **Reply #11 on:** Jan 20, 2012, 10:32:27 PM »

Cool man thanks for the offer.

I finally hit electrical overload and quit working on it. I have had the dash in and out. When I check the gauges they are getting 4.5 volts, per FSM they should have between 2 -> 7 volts.

The OHMs between the terminals on the back of the dash are 25. Which is what they should be per FSM.

So there is a disconnect between the sending unit and the gauge? Or bad ground to the gauge?

The two gauges are run parallel, on the same wire I think.

Slolyfe · « **Reply #12 on:** Jan 20, 2012, 10:44:08 PM »

fordh8r · « **Reply #13 on:** Jan 20, 2012, 11:55:06 PM »

Ok, so according to that diagram, #16 coming from the gauge is what goes out to the sending unit., #5 is for the fuel sender, #6 is from the ignition sw....do you have a tach and does it work?

Slolyfe · « **Reply #14 on:** Jan 21, 2012, 03:00:06 PM »

Yes Tach and all dash lights work.

fordh8r · « **Reply #15 on:** Jan 21, 2012, 03:14:24 PM »

It's really starting to sound like the gauges themselves have crapped out. Do you have any spares to swap in for testing purposes?

Slolyfe · « **Reply #16 on:** Jan 21, 2012, 04:14:39 PM »

Quote from: fordh8r on Jan 21, 2012, 03:14:24 PM

It's really starting to sound like the gauges themselves have crapped out. Do you have any spares to swap in for testing purposes?

I am going to run by my parents house when I am in town. I think I still have a stock pile of parts in their basement.

If not then I will prob make a new gauge panel and wire up a tach, fuel, and temp.

Although doing research it is common for those 2 gauges to go out together. But both are showing 25 OHMs and the correct voltage. Which is what is puzzling me.

fordh8r · « **Reply #17 on:** Jan 21, 2012, 04:17:36 PM »

That 25 OHMS...did you check that with the gauge removed from the cluster or did you check it while still installed?

Slolyfe · « **Reply #18 on:** Jan 21, 2012, 04:33:30 PM »

While the cluster was sittin on the bench.

fordh8r · « **Reply #19 on:** Jan 21, 2012, 04:34:49 PM »

Gauges still in the cluster itself? Or is that how it is suggested to be tested?

Slolyfe · « **Reply #20 on:** Jan 21, 2012, 07:36:45 PM »

Quote from: fordh8r on Jan 21, 2012, 04:34:49 PM

Gauges still in the cluster itself? Or is that how it is suggested to be tested?

Yea, gauges still in the cluster. You just need to hold the probes to the brass terminals on the back of the cluster

fordh8r · « **Reply #21 on:** Jan 21, 2012, 07:50:15 PM »

Shouldn't the gauges be removed from the cluster when you check their resistance so it doesn't feed back from another component?

Slolyfe · « **Reply #22 on:** Jan 25, 2012, 09:58:46 AM »

Hey tommy! It was the gauge cluster. I threw a new one in and it works great. Thanks for all you info on this. I must have broke the ground side solder in there somewhere. Thanks again!

fordh8r · « **Reply #23 on:** Jan 25, 2012, 10:01:25 AM »

Awesome! Good work, Bro! Always glad to help!

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