The Dodge Challenger Message Board

Hi,my 383 rt has a problem,dim headlights and indicators,improve when revs go up and dash lights brighter with higher revs,is this a voltage regulator problem as my battery is good,also indicators dont flash at idle but will when rev engine.thanks

Sounds like the alternator is not putting out enough voltage at idle.

This COULD be the voltage regulator. But I suspect not.

What is more likely is that you have high resistance in the circuit from the alternator output to the dash.

Alternator output goes to the ammeter in the dash before it goes anywhere else. That one wire carries all the current for the whole car and it goes through one spade terminal in the bulkhead connector to get to the ammeter.

This is one of the most common problem areas on Mopars. This connection in the bulkhead gets tarnished with age and then starts to burn out.
The high resistance caused by this bad connection reduces the voltage available at low rpms.

A link that will help you;

http://www.madelectrical.com/electrical ... uges.shtml

Although this is a good way to get around the problem there is also a slightly easier way.
This is to repair the existing connection as it was but to then run a second heavy wire (fused) directly from the alternator to the BATT terminal on the starter relay.
This will reduce the amount of current going through the connection by at least half and drop the resistance in the wiring considerably.

Also worth doing is adding headlight relays;
http://www.madelectrical.com/electrical ... ghts.shtml

Thanks Dave,have been reading thru other electrical problems here and have seen your comments about the bulkhead connections,altmeter moves hard over with revs,tryed to compare with my other challenger but doesnt have ralley dash altmeter as wss ,new to this forum,have other electrical issues i will ask about once i sort this out,car has sat for many years after restoration,thanks for your help and will check all connections and check out those sites,great message board with heaps of good advice on all sorts of issues

If the voltage goes over 14.5 volts when you rev the engine (stick a volt meter over the battery) then your voltage regulator is buggered.

Have also noticed today that if i turn on the lights when engine is running then also turn on indicators my engine starts to miss as if not enough power going to coil,would this all tie into the car not getting the power it needs because of faulty connection at bulkhead or voltage regulator,may take the voltage regulator off my other challenger and try to see if any difference.

Don't start swapping parts around. Use a volt meter. It is the only way and will come in very handy for all sorts of jobs in the future.

ok ,will do, not too up with electrical issues,more of a mechanical guy,thanks for your help

You are never too old to start learning.

The problem with 40 year old electrics is that you are always going to have problems from time to time. Being able to find faults is a useful skill that will help you in all sorts of ways for the rest of your life.

Think of this as an oppertunity for self improvement.

Buy a multi meter that measures volts and Ohms (resistance) at the very least. You can also get automotive meters that also measure Dwell (for points) and RPM.

Using a suitable volts scale (0-20 volts say) put the +ve and -ve probes on the battery and see what the idle volts are. Then increase the rpms and make sure the voltage does not go over 14.5 volts. If it goes 15 volts or over with rpms (no regulation) then get a new regulator.

If it does not go over 14.5 volts no matter what rpm you have then the regulator is OK.

I knew NOTHING about auto electrics until I bought my Challenger when I was 30 years old. The car had electrical problems all over it when I got it. So I had the learn fast.
Now I can completely re-wire a car if I need to. In fact I just did.

check the grounds on the engine-bat-frame- nice and clean and tight!

check amp meter connections, bulkhead connections is a common problem and also look at the harness connection for the ing. switch- look at the heavy cable connections for burnt, discolored plastic!!!

John Mac

Hi Guys,have bought a multimeter today and done a test on battery,reading 12.4 volts,started car and no change,run car up in revs and still no change across the battery,great thing these multimeters as you said dave i will learn heaps more with one of these,hope to get as good as you with diagnosing electrical problems,also disconnected bulkhead junction and this is what i found,secound from top left connection looks burnt,i am assuming this is the connection which comes from alternator to ammeter then feeds rest of car,please let me know as dont want to get it wrong,also a few pics of my challenger,thanks

That will be the one. You should have more like 14.5 volts at the battery when the engine is running so it sounds like you have high resistance in the circuit.

One of the two methods I already described should sort things out for you.

Thanks Dave,have got it fixed,have 14 volts when car is running now and lights are bright and indicators flash at idle,great help cheers

70- with the bulkhead connectors- carefully with a needle nose pilers- squeeze the two side of the female connector together so that the male connector goes in tight- it doesn't take much pressure to do this- them use some dielectric grease in all the connections to keep out the moisture.

John Mac

Thanks John Mac,have done as you suggested,also what Dave suggested with bypass from alternator to starter relay,everything is better and brighter now with headlights and indicators,thanks Paul

I finished up added relays to the factory headlights (referencing this thead for guidence). They gained 2.3 volts at the bulb connectors with the conversion! What a major improvement.

Sorry,, just had to tell someone.

Big difference eh?

I'm considering doing this upgrade, as it makes total sense. But I want to retain operation of the AMP gauge, so does this procedure still apply?
If not, what would I do to retain the AMP gauge but still upgrade to power pathway?

Thanks

I've read a post on here before that gives complete instructions to do just that mod. Use the search tab on the top of your page. If my memory is correct it was a reprinted magazine article or some thing like that, very comprehensive instructions tho'.
I would seriously consider replacing all the wiring system if you got issues with old and frayed wiring and poor contacts. Consider a kit by Painless or similar, lot of people on here have used thaat brand, makes a very nasty job very easy. Probably cost you as much in wiring components as a whole loom would in the end, plus the added benefits of having higher performance and fire resistance, not to mention the in-built protection of the circuits and the ease of troubleshooting problems.

Found it http://www.madelectrical.com/electrical ... uges.shtml

That article has probably save quite a few Mopars from electrical and quite possibly, total melt down.

If you want to keep a functional original looking AMP gauge, Redline Gauges used to do a retrofit to the original. You would need to send in the unit though and there maybe some down time.

If you do try them please let us know how it works out.