Fixing A-body Electrical Problems
Not starting: 1974 cars only
The seat belt interlock system was unique to 1974 models, and was mandated to prevent drivers from starting their car until their seat belt was buckled. It relied on a relay under the hood, but the easiest way to start the car is to disconnect the wire underneath the seat. (thanks, sub1moa)
Instrument panel: all A-body cars
Stanley L. Martin’s 1973 Dart Swinger's temp gauge had stopped working, and he assumed it was just a bad connection. The next problem was the gas gauge, which read low. Five days later, the needles pegged. He wrote:
If YOU start having gauge problems, including unexpected low readings, pull the instrument panel fuse (#6 on his 1973) immediately.
By the time he did this, his board had been destroyed. As he said:
On the back of the instrument panel, top center, is a little rectangular voltage limiter, which cuts the voltage for the fuel and temperature gauges. As of 7/17/95, this part was still available from Chrysler. However, if it fails completely, as mine did, you may burn out your gauges. Both gauges are also still available from Chrysler (barely) but be prepared to pay a good price (~$50 each) for them. [Rick Ehrenberg has suggested replacing this with a newer, electronic version as a matter of course.]
My factory service manual warns that apparent voltage limiter problems can also be caused by a poor instrument panel ground. On the Plymouth Valiant - Dodge Dart (and Duster, etc.) panel, the ground is provided by three metal tabs behind the bottom three instrument panel screws. Be sure these are tight and that the tabs are making good contact with the metal dash supports behind them. Since these have metal behind them, it should be okay to tighten them down firmly.
If you do have to pull the #6 fuse, you will also lose your oil pressure warning light and your brake warning light, so consider that as a 'limp home' capability. If you must keep driving, try removing the voltage limiter - it just plugs into the back of the instrument panel printed wiring board - which should disable just the two gauges. This would be difficult to do on the road, as the voltage limiter is all but impossible to reach from under the dash; and to remove the instrument panel, you must remove the a/c duct (if so equipped) and drop the steering wheel for clearance.
Instrument panel again
Richard Henley wrote:
Recently, I removed the Duster’s instrument cluster to make it easier to work on the wires under the dash. Upon testing everything when finished, I had no gauges working, nor turn signals or heater. A quick check of the fuse box revealed fuses numbers two and six were blown. When I replaced them, they blew immediately. Even with everything unplugged, I still had a short.
The next step was to take it back apart and see if I pinched a wire when I reinstalled the cluster. I found that removing the top left screw holding the instrument cluster eliminated the short.
I took the cluster out and discovered that the wiring harness had been penetrated by the screw. The clip in the upper center of the dash has a second tab to keep the wires from getting to the screw, but the one on the upper left corner doesn’t have that second tab, putting the harness in harm’s way.
I also found a lot of scuffing on the harness wrap where the screw had been rubbing on it. I took the wrap off to investigate the wiring, and found that the insulation had been penetrated on several wires, and the horn wire had been cut clear through, probably several years previously as the wire ends were corroded badly.
I soldered a splice for the horn wire, taped up the damaged places on the other wires, and then used a zip tie to hold the harness on the outside of the clip away from where the screw can get to it. If you have a mystery short you can’t find, now you know one more place to look, and if you have your instrument cluster out, you ought to check this and make sure your wires aren’t going to get screwed up, literally.
Chris North wrote: Until 1968, the parking lights on US cars normally went off when the headlights were turned on. The early Plymouth Barracuda put a jumper between the tail light terminal and the parking light terminal on the plug that attaches to the headlight switch, to make the parking lights stay on when the headlights were turned on. For your Valiant, you can remove the headlight switch and solder a jumper wire between the "P" and "R" terminals on your headlight switch to keep the parking lights on with the headlights.
Fuses and troubleshooting
Thom McIntyre wrote, "After nine or ten trips around the block and blown fuses, I took a look at the alternator, cleaned and tightened up a loose spade connector on it and the fuse in there now is holding up."
When blowing fuses, Sandy Colter suggests (regarding a Valiant VH):
Try unplugging the rear body harness from the main under dash harness to isolate the part of the car that has the short. If you have the body harness disconnected and you still blow fuses, the problem is under the dash or the door/dome light switches. With the harness disconnected and no blown fuses, pull the interior and follow the wires till a problem area shows up.
If you can find a car with a fresh harness, it is not hard to change the whole thing. It breaks into several pieces, with the under dash one the hardest to deal with. I have done several complete harness change overs. I replaced a 340 Dodge Demon harness with one from a 6 cylinder parts car; there were differences but I made it work, as the different parts were separate pieces.
Bill Watson wrote:
The Plymouth Valiant and Dodge Lancer did not get a fuse box until 1962 (they were launched in 1960), when it also adopted a circuit board for the dash lights and gauges. The absence of a fuse box was not uncommon in those days, and accessories used in-line fuses. Studebaker used in-line fuses right to the end in 1966.
The heater, radio, rear window defogger were all options, and all used in-line fuses. The radio and rear window defogger used 7-amp fuses while the heater use a 20-amp fuse. If you follow the black wire from the heater switch you will find the in-line fuse and farther down the line, the terminal block. The wires for the radio (black), rear window defogger (light green), and the dash gauges (black) run off the terminal block. A fifth wire (black) runs from the terminal block to the accessory position on the ignition switch, which is the terminal block's source of power.
The windshield wiper and headlamp circuits had circuit breakers in their switches. The back-up lamps and turn signals took their power from the windshield wiper switch, and thus the windshield wiper breaker. The cigar lighter and interior dome lamp get their power from the headlamp switch and use the headlamp switch circuit breaker.
Intrepid buyers may notice that replacement battery cables don’t quite fit; that’s because Chrysler stopped making them long ago and the aftermarket simply substitutes “Almost-Fit” for the correct cables. Restorers can find good solutions for the negative cable at over $100 per cable. The positive cable may still be available from dealers (P/N 2983649).
More A-body — Valiant, Dart, Duster, etc. cars — fixes and repairs too long for this page
- Much brighter car headlights (Duster test at allpar)
- Electrical diagrams (courtesy of Dave Wordinger) covering 1960s and 1970s A-bodies, for use with alternator and electronic ignition upgrades. Includes some guidance.
- Adding daytime running lights (DRLs; at allpar)
- Replacing and gapping points.
- Bulbs and fuses for 1974 Chrysler A-body cars.
- LED third brake lights (Valiant test at allpar) and brighter tail-lights and sidelights (Valiant test at allpar).
- Tapping into the ignition feed (1974-76, possibly 1968-73 as well; at allpar)
- Upgrading A-body car alternators. (at allpar)
- Other Valiant/Dart (etc.) repairs
- More Chrysler, Dodge, and Plymouth repair tips at Allpar