The Dodge Challenger Message Board

Hey guys, long time but i am still around. I need some help. My rallye instrument cluster seems to have lost power as the speedo, tach and gauge pod went dead today. I have headlights, dome, clock, door ajar buzzer and good ignition - no power to the radio or wipers either. I have never had this issue sine a ground up resto 7 years. I did for the first time get stuck in a heavy rainstorm last weekend and parked the car indoors and then today, no gauges or radio. After driving it for a few miles everything kicked in but soon went dead again. I checked the fuses and they all are ok. I am thinking the voltage limiter is malfunctioning, but my gut tells me a short or ground issue. My fuse box is clean as well. Could the exposed side of the block on the firewall have gotten wet and shorted out something? I am clueless on this.

Maybe a bad connection in the wiring exposed by the rain/moisture. I'd start by going through the circuit, clean and add dielectric grease to the fittings.

Glad you popped back in bro..

what fittings? In the fuse block area? thanks Jon.

isnt there some sort of diode or relay in the gauge pod ,i had mine go out and that was it a little condensor looking thing that pluged in its been many years sisnce i did it so just cant remember, dave would know

This is the back of the gauges on a 70. Follow the wires and check the connections (and grounds) in the circuit. There is a wiring diagram on the board somewhere..

IIRC, the speedo is purely mechanical. And the 5V voltage limiter only supplies current for the oil, temp and fuel gauges.
Having these stop functioning at the same time seems weird...

ok, no further along here. no power to radio or gauges or wipers. Could it be the fuse block got wet on the firewall and some of thise connections arent very good to begin with? If its the voltage limiter on the back of the cluster then would they intermittently get power as it did for 5 minutes yesterday or does that part just die out? Power to headlights is there, dome door ajar etc...really strange. Is their a main connection on the fuse block that carries the power for these things? I can always clean it. I think its a grounding issue but where do I find that circuit?

ok there is also a long screw that holds a piece of trim and it also is the ground, have you tried to attach a wire to the body ,or bezel of the gauge pod, and then to the frame,it needs to be grounded, perhaps the screw fell out,or something shifted, what other accessories work? also in the pic that jon posted there is a little brown box,at the top of the pic, with some wires going in to it, that unit went out on me,do the ground first,and go from there.

ok, will try to ground the bezel but isnt the cluster normally grounded bu the 6 screws that attach it to the dash frame? What ground screw are you suggesting? Also, radio is dead along with wipers as I stated above. Oh Dave where are you?
Steve

Rizrtse wrote:ok, will try to ground the bezel but isnt the cluster normally grounded bu the 6 screws that attach it to the dash frame? What ground screw are you suggesting? Also, radio is dead along with wipers as I stated above. Oh Dave where are you?
Steve

i know those screws might have grounded it , but do know that there is a ground strap in the dash frame and it is on the left hand side of the lower part of the dash, below the heater controls,it actually holds a part of the trim,and goes through the ground strip, and and the to the dash frame it is a long screw, it grounds alot of stuff, but try grounding it first with a wire and see what happens.

With the ignition key on, grab the suspect wire(s) and gently pull and shake them, try to get the windshield wipers or radio/gauges ect to turn on,,this may help locate the source of the problem or the wire that is open or shorted.

Rizrtse wrote:Oh Dave where are you?
Steve

Don't know where to start with this one so i was keeping out of it.

Basically faults like this are easy to trace if you know how to use a volt/ohm meter. It is a simple and quick matter for someone with electrical experience to trace both the power side (is there volts between your power leads and a good earth) and the ground side (do you have continuity between the body of the effected parts and a known good chassis ground).

Unless you can use a volt/ohm meter you are just shooting in the dark.

Will start with the non technical method of turning ignition to "on" position and moving some wires around to get the wiper motor engaged and/or radio to possibly isolate the wire location....when the gauges worked intermittently the other day (once during cruise) the wipers came on the same time. I do have another question - the 70 manual shows a circuit breaker in a wiring diagram. Is that a part that fits onto the fuse box? the only thing I have is a realy of some sort on the top portion of the fuse box, probably for the horn.

The wipers not working is the confusing bit. They have their own connection on the bulkhead connector/fuse box and are not connected in any way I can think of with the gauges. The only common bit I can think of is the chassis.

So I would be making sure the dash and instrument panel metalwork has a good connection to chassis before pulling wires.

ok will do. What aboutthis circuit breaker thing I see in the wiring diagrams

Rizrtse wrote:ok will do. What aboutthis circuit breaker thing I see in the wiring diagrams

When a circuit breaker goes that's it. Not an intermittent event so that may not be your "current" problem. Actually the fuse is a fail safe for another problem in the circuit(s). Only one i know of outside the fuse block is the fusible link in the engine compartment. But that would kill everything.

I would go to the bulkhead and clean all of the connections then check the wires going to your malfunctioning components with a multimeter or continuity light. Good luck.

Jon wrote:
I would go to the bulkhead and clean all of the connections then check the wires going to your malfunctioning components with a multimeter or continuity light. Good luck.

Especially since it happened after it rained. This could have gotten water in it if the rain were that heavy.

Thanks guys. Spent 2 hours cleaning the connections on the bulkhead (which is new and looking good from a big resto years ago). Played with some wires with ignition ON and nothing got power to the wipers, radio, directionals or gauge pod. Dome, map, door ajar, emergency flasher, buzzer all work, and car starts perfectly. Obviously fusible link ok, battery grounded to engine and rad support. I cant think their is a short for this many unrelated elctrical issues to surface unless its in the main harness and that would kill some of the things I see working. So, I am left with thinking Dave you are correct in assuming its a ground issue. Darn cluster is screwed in nicely to unpainted dash frame. Time to have some with a voltmeter test some connections I guess. Gremlins?

You missed an important ground although I doubt it has any effect. The fuel tank ground strap.

Use an ohm meter between a known good chassis connection (with less than 1.5 ohms between it and the battery -ve terminal) and the metal work on the gauges. You should never have more than 2 ohms between any ground connection and the battery -ve terminal including the resistance of your test wires.

will check the ground and then get myself this gauge and test it...thanks for now guys.

Thanks for Moparman1972 for a hint to look at the harness coming from the column and the white connector that comes from it. Most of the loss of power was confirmed on one side of the fuse box controlling the items I listed (basically all those things that need the ignition harness). After a ton of continuity testing (cluster grounded ok) and other power tests, and a ton of wires hanging all around my head, I gently played with that connector and the wires going into it, and you guessed it - everything kicks in with the ignition in the ON position. My issue is not over though - the wires are somewhat plyable, in good shape, but the the natural position of the wires going into the connector (new harness repoped from the resto yrs ago) just doesn't sit in a position to give me power all the time. Any hints other than taping it off to the top side of the column? 3 nights learning wiring diagrams and straining under a dash was not fun. Thansk guys.

Might not have been fun but I bet you sure know how to do it now.

I don't understand why the connectors are not locked together in the plastic block. Are you sure that the metal inserts were pushed all the way home in the plastic block before the blocks were joined together?

I didnt pull it apart last night. It got late and I was just happy to have touched something that made everything work! I know its pushed together tight - something must be off inside the connector. I hope thats it and not a short up in the column. It seemed to work when I made some movement around the connector, and as you know, most of that harness is pressed up underneath the column shields to hide the wires, so its not like the whole thing was moving very much. Tonight I pull it apart and look inside and then start putting everything back together. I havent posted much over the years but you guys are always around when need be - thank you.

i am assuming you checked all your grounds? just because you say that the pod bolts to a steel dash , the whole dash could have lost its ground

I think I found the issue, but how can you check that the dash is grounded nontheless?

run a wire even if you have to run clips to temporaily attach one end to the gauge pod, and another to the frame of the car not the dash frame and then try trouble shooting your gauges just to make sure everything is grounded,that you know for sure and then i would start checking every wire which it seems like you have but what you are doing is learning your way around the electrical system and that is a good thing what do you think you found by the way?

a bad connector in the ignition harness....read above...thx steve

are the gauges working?

yes but need new connector since once I let it go and let it find its natural resting place, the power cuts off due to a poor connection inside the connector....simple fix.