Dash Lights Problem

[Lobo'74]

Been working on Truck over the last week or so. Installed Juliano's 3 point seat belts, replaced the cowl to hood rubber seal and found a hole under the cowl passenger side open to the interior - thats why the floor was wet when it rained - epoxy patched it. Next I replaced the ineffective antenna with a taller one. The radio works much better, but I found the cable running through a hole under the cowl drivers side into the interior, so thats why THAT side of the cab gets wet in the rain. Caulked it for now. Replaced the mismatched oil pressure, temp, and volt gauges with sunpro's. Now they work fine, but after putting the dash back in the spedometer quit working. I had pulled up on the cable when working on the dash. Pushed it down and wiggled the connection going into the tranny back and forth a little. Now the spedometer works again. Turned on the lights tonight to check out the new gauges. They work fine but only the right half of the fuel gauge lights up now, the turn signals are green all the time until you use the turn signal, then the green arrow for the side you are turning to blinks off and on, and the spedometer lights very dimly when the parking lights are on, but goes out completely when the lights are pulled all the way out to the "On" position.

I took power for the new gauges from the same wiring the PO had the mismatched gages attached to. I am clueless as to whats going on. Its a non-gauge dash with the add on gauges mounted about where they go on a gauge dash. Could I have plugged the big dash plug (on the back side going through the flex circuit) in upside down? Is it possible to put it in that way?

Discouraging.

[jmanz69]

Sounds to me like a ground problem. Take the dash off and make sure your connections are tight, also there should be a ground wire from the back of the dash to one of the clips on the metal truck dash as a ground. If it's not there or loose, it could cause a problem. Check for blown bulbs, they will be black when you look at them. Make sure the ground srews on the flex circuit are all there and not broken or pulled thru. That's about all I can think of right now.

[Lobo'74]

As far as I remember, there are at least two braided wires grounding to the metal dash. I'll have to pull it apart to verify. Also, I'll check that there is at least one ground going from the flex circuit to the metal dash. I did remove a ground wire running from a small screw going through the flex circuit to the old oil pressure gauge. I took the ground for the new gauge off of the metal dash below the plastic bezel. I might have to run a ground from that screw throught the flex circuit down to the metal dash area. I thought that was a ground for the old gauge, maybe it was for the flex circuit. I'd think the flex circuit would be grounded by being attached to the metal on the back of the instruments, but wires are not my strong suit.

It'll be a couple of days before i can get back to it to try a fix.

Any and all ideas are appreciated.

[Lobo'74]

Just bringin' this ttt to see if anyone has any more ideas on what is wrong with my dash wiring.

[Lobo'74]

Thanks jmanz69. It WAS a loose connection on the flex circuit. The 1/4" hex screw going through the flex circuit that I loosened to remove the ground for the old oil gauge was still loose. I had reached up under the dash to clip a wire to the screw to run to ground to see if that fixed the problem. When I reached under I found the screw and felt it was loose so I got a 1/4' socket up under there and tightened it down. Problem solved. That'll teach me to not check connections after I fool with 'em.

jmanz69 thanks for the idea - I'd have fooled with it a lot longer trying to fix it without your help.

Is this board a great place, or what?

[jmanz69]

Glad to hear you got it fixed. I hate chasing ground problems. it can take days to find the source. Good news is, it was something easy to fix and didn't cost you any money.

jmanz69