M38a1 Lights problem

[MG777]

Yesterday was the first day i took my m38a1 on a night drive and the drivers side low beam went out. Luckily I had replacement sealed beam which I replaced. Today in the evening the second sealed beam also on the drivers went out.

Also wile driving today the cars lights shut off completely this happened multiple times in row. Every couple of minutes for about 10 seconds the lights go out and come back on by themselves.

Any ideas what is broken? I was thinking maybe the voltage regulator.

Thank you very much for your input.

Marc

[4x4M38]

Marc,
Sounds more like a circuit breaker for the second issue.

Does the A1 have breakers?

Voltage regulator might cause an iffy lamp to go, but two in a row on the same mount? Weird.

Voltage regulator could also be what is causing the breaker to trip if it has one.

[BullRun]

Depending on your wiring layout a loose grounding wire can cause flickering lights too.

[wilfreeman]

I had (have) the same problem. I had 1 go out at a rally night ride a couple of years ago after a full resto. Replaced it when I got home with another used one. Blew that one a few months later.

With advice from this forum, I added a second engine ground and a ground from the light to the frame, and switched to a solid state regulator(to eliminate that possibility since no one knows how to work on the originals anymore). I replaced it with a new production bulb this time.

That lasted the longest - about 6 months. I was at a fire dept. function and someone told me the light was out.

I can't remember which, but it is always one or the other (high or low beam), not both. The Jeep has a new wiring harness, but original light switch and dimmer - maybe that would be where to start looking next.

The 'a1 doesn't have any circuit breakers. Maybe your light switch is going bad (maybe mine is too!).

[wesk]

Several items need to be addressed in this string of posts.

1-Basic DC electrics first. A-Good grounds. B-proper voltage.

2-Check filament positioning when installing lamps. Some filaments do not fare well to bumpy rides if positioned either horizontal or vertical. Try changing your mounting position.

3-M38A1 did not come with the 3 circuit breakers between the dash and firewall or the breaker on the instrument cluster but the main light switch has one inside.

4-The transistorized voltage regulator does not have any serious advantage over the old mechanical regulator. Many folks still work on the mechanical regulators. Mainly because there is a ton of published repair data for them and a reasonable amount of parts. On the other hand the transistorized regulators have very little published data and no spare parts. They are throw aways when they fail.

[MG777]

Thank you very much for your input. I am thinking of replacing the sealed beam with production Headlamp. I found one at Hella "Vision Plus 7"sealed beam conversion headlamp". Do you think this one will work? Is there anything i need to know before doing the conversion?

Thank you in advane

[wesk]

This post was entered as new post and that was not the case. I have transcribed to two posts back to this original post. Wes K

MG777
Member
Joined: Mar 14, 2015
Posts: 10

PostPosted: Sat Mar 28, 2015 2:19 am
Post subject: M38a1 lights go out

Hi all, I already installed a new grounding from battery to car aswell as from engine to car grounding.
My problem is that when I turn on my high beam the whole car lights go out after runing for 5 minutes. They come back on within 5 seconds. I dont know which part I should replace.
Maybe I need to install a relays or maybe replace the regulator?

Thank you in advance [/u]
_____________________________________________________________
ChuckW
Member
Joined: Apr 17, 2005
Posts: 141
Location: Alabama

PostPosted: Sat Mar 28, 2015 3:18 am
Replace your headlight switch, common problem, internal circuit breaker.
_________________
Chuck W.
MVPA #15171
Dixie Division MVC #002
1952 M38/M100
1953 Cj3B Navy/Bantam T3-C
M274A2