I have a 1979 Dodge truck which will not charge. I have checked and rechecked connections, had the alternator checked by a garage I trust but they say it's OK . Are there any other typical problems which I may not know about? The Volt gauge (which I installed bypassing the old amp gauge) reads between 9-10 when running. I put a meter on the battery terminals and it never gets above 10 while running. Lights and options work fine while truck is running (after boosting), but truck will not restart on it's own. Battery has been very dead but will hold a charge after charging. Connections to voltage regulator are not super tight, but I have never found a way to make them so.

I love this old truck, but it's yard ornament status is beginning to really bug my wife. Help!

Jayson
Nashville, TN

Check the voltage regulator. It controls the current to the field of the alternator. The more current, the higher the voltage. One quick check would be to short the battery to the field terminal on the alternator. Voltage should spike. If so, the voltage regulator is not putting out the voltage needed to maintain 13-14 volts with the engine running.

Yeah, keep your 79. My daily driver is a 1977 Chevy LUV.

My tuck has a short in dash for dash light I replaced headlight switch I still don't know where the short is . When I turn headlights on all my gages go crazy . Can't find the sort help me thanks georg hott

I have a Chevy that I was fighting the same problem with, before your truck was built. On mine, it is bad connections to the power feed to the gauges. Try removing the gauge fuse and cleaning its contacts. About a year ago I removed the fuse holder and soldered the riveted connection in it. I am having less problems now than for the last 20 years.

The gaugesand the light for the gauges share a ground. When you turn on the lights, the power feeds back through the gauges.

Yeah keep them running. Mines been going since 1980 and she still is running good. Tripped the mileage meter a couple times I drive so much.

thanks for the advice ill try that . Is there any web sight to find wireing diagram for 82 dodge 4x4 truck

You won't find a wiring diagram at www.factorymanuals.com, but I found a real factory shop manual for my 77 for about $12. Much more readable than Chiltons.

I have a 79 Dodge 3/4 ton truck that doesn't wan't to charge Ive changed the altinator, voltage regulator, starter relay, and battery. I heard that if my alt gauge is broke that will keep it from charging too, my alt gauge has a termanal broke off on it is there any way to bypass this or do I have to have it?

An amp gage has 2 big, heavy wires running to it. All the power to or from the battery flows through them. If power isn't flowing through the gage, connect the wires directly together. Do NOT do that is it is a VOLT meter.

It's the stock alt meter, right in the dash

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Originally Posted by 79DodgeMan

it's the stock alt meter, right in the dash

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I am not familiar enough with 79 Dodges for that to tell me anything. If it has a 0 in the middle and a plus on one side and minus on the other it is an ammeter and you can bypass it and connect the wires.

It has a c at one end and a d on the other

OK, it is an ammeter, the C is for charge, and the D is for discharge. You should be able to connect the heavy wires that run to it together, and allow the charge to flow to the battery.

Need help with this one,

Bought an 79 dodge truck with a 440 motor and I think it's a 920 or 980 automatic transmission. The previous owner wired everything himself. This year I decided to try to start it. Man what a mess, everything burned out and the truck was short of catching fire, luckly I unpluged the battery in time.
So now I have replaced the alternator, starter, solenoid, all gauges because old ones burned out, resistors plenty of fuses and many other items.
I have looked through old automotive encyclopedias and other manuals but none are clear as to what goes conneceted to what as there are many different diagrams.
Can anyone point me in the right direction as to where to find a correct diagram.

:confused:

I have a custom built 1985 toyota 4runner with a 440 in it and the charging system is not charging the battery. I know the alt works because I can start the truck and hold it just above ideal, then disconnected the battery and it keeps running.

I have a 1990 dodge pickup that the dealer says the computer is out and that's why its not charging . Anyone know were I can find a wiring diagram for my truck (online) :confused:

Thanks for any help :D

72-80 dodge trucks use same type wiring and two field alternator. If an alternator doesn't charge there is usually the following to check

1) at back of alternator you can visually see the 6 diodes if one or more are missing alternator won't charge correctly. The two tabs of alternator where the wiring connects have brushes these tend to wear out after awhile.

2) voltage regulaters don't go as often as say a chevy or ford do but do sometimes go bad they are cheap and easy to replace.

3) a common problem is for the bulk head connection to corrode out undo the engine harness connection and check the two THICK wires one is red the other is black.

4) if the dash has an ampmeter and has two thick wires going directly to it they have to be connected for alternator to charge. If wires go to bulk connection to dash then check the printed circuit board for warpage, corroded connections, and that bulk connection wires actually connect.

5) this year truck there is a wire that goes from steering column to dash connection this is a ground wire. There is also a terminal and circuit breaker in wiring in dash area that is sometimes played with.

6) some people think radios are a must and install them wrong. If you having problems remove radio and any stupid connectors. Stock radios have a ground strap and are grounded through the metal of dash. The stock connector has two wires power and lights.


81 - 93 dodge trucks use a bulk connection to body with a big bolt. The alternator circuit is the same as the older trucks with a few different connections the computer isn't connected to this circuit.

alternators changed midway during this time to a different style and rather cheaper junky one. If this alternator isn't working replace.

lean burn systems are sometimes replaced with mopar performance upgrade kits. While this is a good idea its almost essential to have a wiring diagram handy.

4X4 trucks have extra wiring for the indicator.. most common problem is the axle switch.

I have a wiring schematic for 71-80 dodge trucks I'm willing to share. Note doesn't include 4x4 or accesories(power windows,locks, cargo lamp, cruise control)

I forgot to include that some of the trucks with fuel injection from 86-93 have a completely different wiring harness and bulkhead connection. The common problem on these is the power splice bulk connection hidden under the thick plastic cover beside the bulk connection loves to rot.

I have a 1985 dodge ramcharger that I am having the same problem with one of the things that I checked and that was bad was my starter it would start the truck but there was current going through it and grounding it out drawing the power from the battery

Depends on the starter if it's the newer small one it may be possible if the older style that's physically impossible.