So today we kept on diagnosing...
To eliminate that wire under the hood so is not the problem, I would check the continuity of it with multimeter first. Place one lead on the bulkhead wire I showed you and the other on the the end of the wire connected to the sender, the multimeter should beep meaning the wire is ok, no beep wire is no good. If the wire is ok you know that the problem is between the bulkhead wire and the gauge or the gauge itself.
Did this and it beeps, so the wire is good.
What we also did was (with the plugs from the bulkhead removed) placed on lead from the multimeter on the female bulkhead connector and the other lead
to the male connector/pin on the plug that connects to the bulkhead.
Tried that with ignition on and off. It did NOT beep.
But i think this is probably normal? I just tried it since we already had it apart...
We used contact spray and compressed air.
that will not work, you need to use sand paper or a small file to clean both connectors. (Male and female)
to clean the bulkhead female connections disconnect the three plugs. Then push on the two tabs at the top of the bulkhead to release it. Then push the bulkhead in towards the inside of the car. Then go inside and pull it down so you can clean the connectors. Done it many times on different cars. Next get a small screwdriver and press it into the little slot to release the connector from the plastic bulkhead. Do one at a time so you will not mix up the location of the plug. Clean it and then take small pliers to close up the gap a little so it will make good contact with the male plug when you connect it. Make sure you bend the tab up before putting the connector back in to the plastic bulkhead so it will stay in place. When done just push plastic bulkhead into the firewall hole till it clicks in place, there is only one way it fits. You can use the screwdriver to release the male plug connectors to, so you can clean them. Before connecting them put some dielectric grease in the bulkhead connectors so they will not corrode again. Do all the connectors once and you will not have to do it again in the future.
I suspect you did it on non A/C cars? Because the heater/ac core (box) is in the way. I can't pull it out.
I can barely see it and can't even reach it with my fingers.
We also tried to pull the bulkhead out in the engine bay direction but this seems to be impossible as well.
Anyway we still cleaned both the male and female pins/plugs with a small file without removing the bulkhead as good as possible.
-> Gauge still does not move
you said you grounded the wire with the key on and the gauge did not move.
After cleaning the contacts as good as possible (without removing the bulkhead) we also cleaned this plug again (with a file)
and tried the grounding again while the engine was running -> gauge does not move.
We also measured the voltage with the multimeter while the engine was running
Its not zero but pretty much all over the place, see video:
Is the voltage limiter working?
Where is it located and could it be responsible for ONLY the temperature gauge not working? Also how do i test it?
The fusible link looks like the insulation is frayed? Bad sign there. The engine/alternator harness leads a hard life with the heat it takes. I know it's expensive to buy from the states for you, but I'd just replace the engine harness for safety's sake. Then you'll have a new temp and oil gauge wiring, as well as the alternator and ignition.
We've already seen it. Meanwhile the wire broke apart by itself when we removed the connector.
We temporarily fixed it with a luster terminal but i plan on replacing the whole fusible link/wire.
Can this be bought somewhere? Would almost prefer good NOS but on the other hand that isulation is also 50 years old...
All in all the harness does not look all that bad (not mint either) so i'm not really hot about replacing it right now.
But is there an NOS or stock reproduction?
-----
We will do one more test by bridging the male pins of the plug that connects to the bulkhead with the female ones of the bulkhead
with wires that have these connectors on the ends:
and then testing again with the multimeter while the car is running.
Just to make sure its not the connection on the bulkhead at the engine side.
Question:
Do we have to bridge all 8 connectors on the mid port from the bulkhead for this test?
Or which ones do i need to bridge for this test?
But at this point we are pretty sure the problem is NOT located in the engine bay but BEHIND the firewall.
I also tried wiggling on the wires unter the dash, especially the ones that go to the bulkhead while my dad was watching the gauge
but unfortunately it does not move at all when doing so.
I think its probably either a loose connection on the back/dash side of the bulkhead which means -> removing the heater core (box)
Or at the gauge cluster -> which means dropping the steering column and pulling the cluster out.
Or a bad wire somewhere inside/under the dash.
I'm not sure if i want to do this right now. On the other hand the heater core needs to be replaced anyway and the clock is also not working
since i got the car.
Is there a good youtube video or tutorial with pictures for removing the gauge cluster and/or heater/ac core/box?
Also when i look at the wiring i get the feeling that somebody (or multiple persons) already touched that in the past since there
is tape on it and i'm questioning if all wires and locations are stock.
Oh man i was hoping i would NOT have to deal with shaddy work from previous owners/restorers since this is a survivor car...
I never had another mopar so i dont know if its stock or not, tough.
