All my electrical woes.

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Backally

Backally

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I have posted on here a bunch of times this past winter on various issues and have gotten a lot of good advice. Giving it one last shot on three issues, but I think I may be over my head. The car is a 70 Duster, 340 with a rallye dash which I purchased last fall. Been doing various things on it throughout the winter hoping to get a good riding season out of it this year. I do have a service manual and have downloaded schematics from this web site but I'm not an electrical guy so need help.

First is my radio, which I posted before about. Insert the key into the ignition switch and it powers up. This really doesn't bother me other than it's wrong. Car did not have a radio in it when I got it, got one refurbished and installed new speakers and the radio. The plug the radio plugs into has a yellow wire, a black wire and two red wires. Wiring diagrams I have do not show radio wiring at all.

This past week I had a fusable link on the engine bulkhead connector smoking. I traced it to a wire from the fuse box to the tach which had gotten pinched when I was reinstalling the steering column. I hope. I fixed that, but now my instrument cluster (oil press/gas gauge/water temp) does not work. Ampmeter still works. I see on other posts to look for a voltage limiter, could that be it/what does it look like and where would it be? Can it be tested or is it a cheap and easy to find replacement?

Third and lastly, my heater fan quit. Worked two weeks ago. Don't know what I did to that. Is there a way to test it before I pull it out? Have no idea how to get it out so that would be another learning experience.

I am sure I will get the rewire the whole thing answers but that would be a winters job for me (if I even want to attempt it) and I really want to drive this thing this summer. Driving seasons are short in central Wisconsin. I am not very competent with a volt meter, so it may come down to me finding someone around here that knows mopars, or else paying for someone else's learning curve while troubleshooting. Not a desirable thought! Thanks for any advice.
 
The radio is wired wrong. Yellow wires are dome lamp among others, but not the radio. If your car has a interior light timer tied in with the ignition lock cylinder, that's why the radio comes on when the key is inserted.
The voltage limiter is inside the fuel gauge.
I dont know where the tach gets 12 volts but since it and the limiter, and the blower motor all get 12 volts at switch on, thats a clue to where the new problem is.
I have 70 model wiring diagrams and I'll help any way I can. You'll have to promise you wont pinch any more wires LOL
 
I figured you or 67Dart273 would offer to help. I wish you lived next door! The radio is low priority right now as it does work. That's one I can work on over time. The tach wire that I pinched and started all my other issues :violent1: runs from the the fuse box to the bottom of the tach, with a black wire running from the top of the tach to the coil. It did appear to be newer wiring so I am wondering if the car didn't have the rallye dash originally and the guy before me installed it.

Is the voltage limiter something that can be changed or tested or would I have to replace the gas gauge? And can that be done, or would I have to get the whole instrument cluster? Where would you look for a problem? The instruments just died a day or so ago, the fan was a week or so back. But have had my hands up there so probably messed something up. But looking I cannot see anything obvious pulled off.

Backally
 
You will have to change the gas gauge are send it off and get it rebuilt. There is a way you can do a add on on the cluster but I don't know how to do it. Good Luck Ronnie
 
When wiring gets chopped up like this, it's REALLY difficult to troubleshoot "by remote control." I'd say you need to work on a local guy who knows wiring.

Decide if you want to rewire it as per stock, or aftermarket, like some of the wiring kits spoke of around here. I think it's Abodyjoe likes "American auto wire" or similar. Contact him--he's got some documentation online for that

I don't really like Painless and Francis kits --they both kinda ignore us Mopar guys. I bought a "used sorta as new" Painless kit off Craigslist, and basically just used the fusebox and part of the attached wiring.

Do you have a shop manual? You can download them on this site.

"MyMopar" has some wiring diagrams, but they leave out the seat belt interlock system, and some of the accessories you might have.
 
I'll look into the wiring diagrams tomorrow morning. Since the 3 gauges quit at once we know the limiter isn't working . More later
 
Since you are gonna be pulling the cluster; bypass the ammeter, and install a voltmeter. We just had to get a new board for a 69; old stuff, once you put your hand up there, things break. And we broke stuff, pulling it out the correct way.
 
The ammeter is totally separate from the rest of the cluster, just 2 dedicated posts. I am preparing a post on how I upgraded my alternator and kept my ammeter.

In my 65, the radio wiring was a separate "add-on", dedicated wires (red & org I recall) that "daughter spade" off the fuse box and run straight to the radio (end in a 2-wire 57 terminal).

The fuel and temp gages work off a 5 V regulator that in your car is a small metal can plugged into the back of the cluster. If it has failed, no big loss since you can get a much better electronic version for ~$25 on ebay. Order it w/ spade lugs and it should plug right it (3 wires). You stick it on w/ Velcro. The fuel gage can get burned up easily, but I think the temp gage is pretty robust, so likely it is your Vreg or maybe just the power to the cluster. I don't know about the oil press gage.
 
Is it possible that there in another pinched wire? or something else got pulled loose while finding the pinched tach wire?
Fuel and temp run off of the voltage regulator, but the oil pressure does not so it sounds like a loss of power to me.
 
Reading the service manual it gave test of the voltage limiter by putting a lead on the temp sending unit, turning key to run and looking for fluctuating voltage. I did that and had 0.037 to 0.036 volts. Is that enough to indicate that my voltage limiter is OK? Troubleshooting guide in manual said to test voltage limiter, then look for open circuit on battery side of limiter. I will be unwrapping all the wires and looking for that. It is entirely possible I have another wire pinched or melted when the fusable link was smoking. Anything is possible with me and wiring.

I leave out of town today for work, will work on it a bit this morning and then may not get to it till mid week, but keep the ideas coming.

Thanks
Backally
 
Backally said:
Reading the service manual it gave test of the voltage limiter by putting a lead on the temp sending unit, turning key to run and looking for fluctuating voltage. I did that and had 0.037 to 0.036 volts. Is that enough to indicate that my voltage limiter is OK? Troubleshooting guide in manual said to test voltage limiter, then look for open circuit on battery side of limiter. I will be unwrapping all the wires and looking for that. It is entirely possible I have another wire pinched or melted when the fusable link was smoking. Anything is possible with me and wiring.

I leave out of town today for work, will work on it a bit this morning and then may not get to it till mid week, but keep the ideas coming.

Thanks
Backally
Click to expand...


That should be a 5 volt reading at the volt regulator.
Sounds like there is actually no power there except a little bleed back through the line.
 
i had the same prob with my gauges on my3 cars there was some pins broke off the main plug on one car. re soldered them back on and the voltage limiter was gone on the other two cars i got the iv3 voltage limiter from dash worx for the rallye dash and instaled them on all 3 cars everything works as it should . you need to disable the old limiter instead of bending the points like i was told i used the plastic they use in starter motors for insulation and put it between the points to disable them . it iwill be very rewarding when you turn the key on and everything works as it should.and if i can do it you can to
 
I am attaching some pictures I took this morning of the fuse box, the left side of the instrument panel and the right side of the instrument panel. You can see on the fuse box the red wire added to go to the tach. I do not see a box going to the instrument cluster, just a cylinder. Would that be my voltage limiter? So far nothing real obvious that looks burnt or pinched. I checked a lot of the push connections and they all seemed tight.
 

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The limiter on your car is INSIDE the fuel gauge. Any switched power TO the cluster is NOT FUSED and comes right off the ignition switch. I don't keep track, but I think on my 67 (obviously different) it "Yd" off right at the ignition switch, that is, the DARK BLUE ignition feed comes right out of the switch, Ys off to the cluster and out through the bulkhead to the ballast resistor.

So none of the "Ignition run" power goes anywhere near the fuse box.
 
S**t. Sounds like I need to send in the gauges to have that replaced. Any recommendations on who to send it to? Anything else that should be upgrades at that time?
 
I've got the wiring diagrams here in my lap. I may not be able to help though, here's why I say that. I can see the red with white tracer that should power your radio in my diagram and in the picture of your fuse box. Since you already stated you're not conserned with what you already know is wrong,
""The radio is low priority right now as it does work. That's one I can work on over time.""
how can I possibly help you ?

I will tell you something you wont find in the service manual.. The gauge voltage limiter or nothing else about the instrument panel will function properly while the panel dangles from the harness connectors.
The pot metal housing requires chassis ground that is achieved though the panels mounting hardware. If you want to do switch on diagnosis while the panel is out you will need to supply a ground jumper. (These sort of things aren't in the manual because a qualified service tech should know the basics. )
I highly recommend adding a dedicated and perminate ground wire.

Going back to the pic of your fuse box, the tach wire is in the wrong place. That added on spade with the large red w/ white tracer is battery feed for headlights and such , hot at all times.
The add on spade beside the large black wire is your accesory port for the tach. The large black wire is hot in run and comes from your ignition switch. It feeds power to the heater fuse and the radio fuse. It look like its been over heated too. If it hasn't failed at this fuse box end it may have failed at the ignition switch connector.
Hope something here helps
 
Didn't mean to sound nonchalant about the radio, but my big focus is getting the gauges. Scares me not having oil pressure/temp gauges working. Just pulled the panel out this morning to be able to get at things. I can trace wires easier now, so will switch the connection for the tach, trace the black wire to the ignition switch and see if make sure it is good and also look at the red/white radio wire and figure out what's going on with that.

At the airport now, so that stuff will have to wait until Tuesday.

Will post what I find later this week.
 
67Dart273 said:
The limiter on your car is INSIDE the fuel gauge.
Click to expand...

67Dart273 is probably right, since I don't see the rectangular Vreg in your photos. I assumed your 70 Duster had one because my 69 Dart did. Maybe the Rally clusters, being low volume, were on a longer redesign cycle. Indeed, your fuel gage looks like the one in my 65 Dart, with the long pin sliding in the copper tower. If you have internet while on your trip, look up the IVR Vreg on ebay that others refer to. They have a great explanation with photos showing how to bypass the one in your fuel gage and installing the modern one. As others, I did not bend the arm back in mine, but just slipped heat shrink over it to disable it.
 
If you'd like, PM or call me. I have a small side business repairing Mopar gauges. I specialize in the electroluminescent gauges in the first gen Chargers, but have rebuilt several A body Rally clusters (including the one in my 71 Demon 340). There is more to the gauges not working than just the voltage limiter, if the insulated nichrome wire is cooked inside the fuel/oil press/temp gauges, replacing the voltage limiter inside the fuel gauge with an external one won't solve the problem. Be happy to walk you thru some troubleshooting if you'd like. My contact info is on my website, www.thegaugedoc.com.

Mark
 
Does the round connector on the back of the fuel/temp/fuel gauge just slide off? Is there anything to make it come off easier?
 

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So got all the wired unwrapped and started tracing wires. Looks a lot more logical and a lot less intimidating when the tape came off. Didn't find any wires that were broke, but did find two that looked like they had been hot. One was the black wire in the fuse box that comes from the ignition to the connector in the fuse box Redfish had mentioned earlier, the other was the red hot wire going to the ignition at the pin hooking into the steering column. Although both looked like they had been hot at those spots, they both had good connections and the wire itself looked good.

Checked connections I could find between plastic connector that goes to steering column and pins in back of gauges. All seemed good. Looked at all the wires from the pins behind the gauges and they looked good as far as I could trace them.

Found red wire with tracer for radio on fuse box. Followed that wire and found a connector tucked up in all the wiring. Had the red wire with tracer to fuse box and a white wire in the connector together with it, and on orange wire that ran to the fuse box, position F in the service manual wiring diagram. Seems to me F would be hot, with the red wire switched with the ignition and the white going someplace else but just needed to be switched power. can't test it with the radio until I get things back together but seems like that makes sense

Moved tach wire to spade in middle of fuse box, should be switched connection now.

Is it possible to test the steering column wires other than just look at them? Steering column in on my bench, can I just turn the key to run and see if there is connectivity between the proper pins without shorting out? If that checks out, I think the voltage limiter is the culprit for the gauges unless someone comes up with something else. And as that is inside the gauge UPS here I come.

Haven't looked at the heater fan issue yet. But as I haven't seen any wires anywhere bad I am guessing burned out fan. Is there a way to jump that an check it?
 
One thing at a time please. So you did find the radios harness plug. Red is radio power. The orange is idial illumination. It gets power from the fuse box but only when the headlight switch ( park ) supplies power to that fused circuit.
The large red wire in the ignition switch connector is power into the switch from the fusible link. The black wire is that same power throught the switch in on position to the fusebox. That wire does have a welded splice where it branches to wiper switch,instrument panel including the limiter, etc..
Like I said before, you can power it up with a ground jumper on the instrument panel. Beware those 2 connections at the amp gauge ! Those are hot at all times.
Once we know the instrument panel and the fuse box is getting power then we can go after what works and what doesn't.
hop this helps
 
The factory radio has two, 2-wire pigtails on it. One with a T connector with the red w/tracer (12V+) and an the other is an orange wire for the dial light. The other pigtail has the 2 speaker wires. The gauge problem is most likely the voltage limiter built into the fuel gauge but I'd check to be sure that power is getting to the gauge first and that there is a pulsing 5V leaving the gauge at the middle post under that plastic cap. Redfish has a kit to convert to a solid state limiter that you can buy or have him convert your gauge. The heater motor can be hot wired to see if it works or not. Just run a 12V+ wire direct from the battery to the motor + lead. I like to see what kind of amperage it's drawing to as they can melt the wiring and switches if they're drawing too much.
 
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