Few electrical questions

[MudFlap]

Here's a few questions, I think most should be pretty easy.

1. Fuel Gauge. When I turn the ignition switch on, it moves up to the "Hey dumb-***, yer fixin to walk home" (E) mark, no matter how much fuel I have in it. I dunno what it'd say if it were actually empty; I've personally never tried it. I'm thinkin float.

2. Dome Light. It's really dim. With or without the engine running. I hooked up the multimeter to it a bit ago with the engine off (radiator is in the shop), and she's getting 12.5 volts. Wrong bulb maybe? I checked the contacts; they are all clean.

3. Instrumentation Lights. Reasonably bright for the Ground Speed Indicator, but get dimmer as you go out. The ammeter is pretty hard to see at night. Burned out bulbs maybe?

4. I bought this ole girl and drove it straight to work, only to discover the headlights didn't work, and the turn signals were doing funky stuff. Found the headlight ground disconnected up by the battery. The battery cable not only connected to the engine block, but also had a smaller lead that wasn't connected. I bolted these two together to the core support, and voila, I had lights. I do notice the headlights dim a little and the turn signals slow a little at idle. This 72 had the original voltage regulator in it (unfreakinbelievable - try getting a China made piece of **** to last 40 years). I bought a new one, but haven't cranked the car up, due to the radiator being out of it.

5. Standard Blue Streak used to be the premium name in ignition products, but alas, their voltage regulators are made in China now. So are the Borg-Warner, and the BW Select. Does anyone know of an American made VR? I simply refuse to feed the communists. Their **** is made by the children, for the children, and they pass the slavings on to you. I see MOPAR performance, and MOPAR repro on eBay. Whaddya think? Any experience with em? I ended up buying one at AutoJunk. Their DuraCrap brand said made in USA from foreign parts. Might as well be made in China.

Thanks for yer time. I'm no stranger to Ma Mopar - I've had a 79 PowerWagon, 88 RamCharger, 79 LeBaron Police Chaplain's car (Police suspension, 2bbl 318, full cloth bench seats, spotlight, Police wide wheels and tires), 01 Ram and 01 Durango. The 79 PW was my labor of love, and I'd give just about anything to have her back. She's the one who converted me from a die-hard Queervolet guy.....

 

[MudFlap]

sig test

 

[RedFish]

Grounds. each bulb in the instrument panel has a screw beside it to provive chassis ground the the housing . Then the housing has mounting screws conducting the ground path to the dash. There should be a ground wire between the firewall and right rear of the engine block to complete the path. Somewhere around 72 or3 the factory added a ground wire from the neg battery cable to the radiator support which improved the path from body, headlights, park turn signals , etc..
as for the voltahe regulator, buying imported parts from your local part store does support that retailer, your local economy.

 

[67Dart273]

1. Fuel Gauge. When I turn the ignition switch on, it moves up to the "Hey dumb-***, yer fixin to walk home" (E) mark, no matter how much fuel I have in it. I dunno what it'd say if it were actually empty; I've personally never tried it. I'm thinkin float..

Probably, maybe. Does the temp ga. work? These cars have an instrument regulator "instrument limiter" which provides lower (originally pulsed) voltage to the temp/ gas gauge. The pins on the connector for the cluster PC board could be loose, the voltage limiter could be flakey, the gauges may not be making contact where they are bolted to the board, and the board/ cluster may not be grounding.

The tank sender may not be grounding, or the push--on wire connection at the sender may be corroded. Ground the wire back at the sender and see if the gauge quickly heads for full. Don't leave it on for long. SOMEWHERE I have a spec on full/ empty sender resistance, you can actually buy a resistor close to that at Rad Shack and see if the gauge is somewhere accurate, by hooking the resistor from the sender wire to ground. That will provide you with an "end to end" check and then you'll know for sure

2. Dome Light. It's really dim. With or without the engine running. I hooked up the multimeter to it a bit ago with the engine off (radiator is in the shop), and she's getting 12.5 volts. Wrong bulb maybe? I checked the contacts; they are all clean..

How did you check voltage? If you checked with the bulb OUT, you are not really checking. Put the bulb in, pull one of the door switches, unhook the wire, and give it a "known good" ground with a good clip lead. If you get a bright lamp, you have grounding problems at the switches. If not, backtrack to see if the bulb is actually getting full 12V UNDER LOAD. It might be resistance/ corrosion in the supply line

This might be easier done by rigging a junk socket, or soldering leads to a stop/ tail lamp for test. Anyhow, "rig" a test lamp with a probe, an NICE BIG lamp like a stop/ tail lamp. Ground one side, and clip your voltmeter to the probe, so that when you probe with your "big" test lamp, the voltmeter measures also

Now probe into the hot side of the dome lamp socket, and read your voltage This will tell you if you ACTUALLY are getting voltage under load

3. Instrumentation Lights. Reasonably bright for the Ground Speed Indicator, but get dimmer as you go out. The ammeter is pretty hard to see at night. Burned out bulbs maybe?.

You should be able to tell if bulbs are bad. Might be time to pull the panel and take a look. You can download some service manuals right from this site

http://www.forabodiesonly.com/mopar/showthread.php?t=132309&highlight=manual,+download

Pull the column mount bolts out of the floor, pull three more studs/ nuts up under the dash and drop the column down in the seat. Pull the dash screws, unhook the battery ground, and pull the speedo cable. Pull out the cluster and if necessary, remove the ammeter wires for more flexibility.

Inspect the pins on the circuit board connectors for loose/ corosion, inspect the "socket" where the instrument regulator mounts, and loosen/ tighten the gauge studs to clean the pc board. Inspect / clean under the lamp sockets, the PC board for corrosion. And of course, replace bad lamps.

Find the ground points on the board, and they will be screwed to the cluster. Loosen/ tighten those screws to "scrub" the connection clean, AND add a separate ground wire from one of the ground points on the board(s) to the framing in the dash behind the cluster.

Inspect your headlight connector for "meltage" and damage. Pull it on/ off several times to clean/ scrub the connections.

Your instrument power on those is a trick. The power comes off the tail lamp circuit, goes to the switch, and BEFORE it goes to the panel lamps, it then goes through the inst. fuse in the fuse panel.

Headlights are not fused. The switch headlight power comes off the main harness splice, not fused, to the switch, which has a breaker built into/ onto the switch.

So dim dash lights might be

a few burned out, bad connections in the sockets/ PC board, a flakey lamp dimmer on the switch, or bad wiring/ connections in the fuse box.

I do notice the headlights dim a little and the turn signals slow a little at idle. This 72 had the original voltage regulator in it (unfreakinbelievable - try getting a China made piece of **** to last 40 years). I bought a new ..

Read this article from Mad Electrical:

http://www.madelectrical.com/electricaltech/amp-gauges.shtml

and some more good articles from there:

http://www.madelectrical.com/electrical-tech.shtml

If you scroll down that first page, there's a simplified diagram of how legacy Mopar electrical is setup, and it CAN have problems (30-40 years old) The main battery feed AND the main alternator charging line go into the interior on two separate connections in the firewall connector. BOTH these connections, as well as a COUPLE of others, are subject to "meltage" and other corrosion damage. It would do well to pull the bulkhead connector apart and inspect it. Some guys feed new wires straight through the connector, others bypass the ammeter

So there are a number of things that can cause dim lights:

Either/ both of the main feed bulkhead connections bad.

Bad connection at the ammeter, or a failing splice in the harness under the dash

Poor connection at the headlight switch, or a failing breaker on the switch.

Poo connections/ feed from the switch to the dimmer, from the dimmer through the bulkhead, and poor connections at the headlights, and....

poor grounds at the headlights.

Last SOME of this dimming at low RPM is characteristic of these cars.

Upgrading wire size, installing headlight relays, dealing with the bulkhead connector, possibly bypassing the ammeter, all add up to more stable voltage.

IN THE END you may have to go to a more modern alternator ("Denso") to finish off the last of the problem.

My legacy 70/ later alternator on my 67 Does well.