Lighting Help

[WayneR]

I am having problems with the headlights on my 71 M38A1 CDN3. Everything is working fine but I have no low beams on the headlights. I have changed the light cluster with 3 or 4 new ones as well as the dimmer switch on the floor. All the wiring looks good and the headlights are new. Any help or ideas will be greatly appreciated.

Thanks in advance

Wayne

[Phil Waterman]

Hi Wayne

First diagnostic question, did you have low beams before this problem?

Or is the beginning of the problem unknown?

I'm in the midst installing the head lights on my HUP and a similar problem high beam no low beam. Which was actually caused by two different problems power to the wrong terminal on the dimmer switch and open ground.

Cheers Phil

[WayneR]

Hi Phil

This was existing when I picked up the jeep. Orriginally I was told it was a light cluster issue but after replacing it several times I am trying other avenues.

I will look at all the groundings as well as the wiring on the dimmer switch.

Thanks for the information.

Wayne

[Phil Waterman]

Hi Wayne

I suspected that this was an existing condition, also suspect that you will find that it may well be a incorrect connection I'd start at the dimmer switch. Do you have a wiring diagram to check the connection of what goes where?

There are I believe three wires coming to dimmer switch if so it will basically light the bulbs on either high beam or low no matter how you connect the wires.

Dimmer switch should have one connection marked as power or bat this should be getting power from the light switch. The other two terminals are for the high and low.

As I said just went through this with my HUP.

Cheers Phil

[SteveJ]

The dimmer swithch is where I would go. Had a similar event on a friends M38 and the wires to the switch were on the wrong terminals.

[rob love]

Wires no 17 and 18 are for the low and high beam on the headlights. Wire no 91 at the headlights is ground. Make sure the headlamps are wired correctly and then check for continuity from the terminal at the hi/lo switch to the wires at the headlamp.

At the hi/lo switch, you will notice that one of the three holes is ribbed on the outside. This is the hole where the power (hot wire) should go into.

Unrelated to your problem, but it was common for the drivers to cross the wires at the headlamps during replacement of a bulb. If a headlamp wire no 91 is not wired to ground, you end up with a very dim headlamp bulb and a hi beam indicator lamp that will not go out completely on low beam.