Lighting Help

[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.

[Frank v R]

Did you install the seal beams or did they come with the vehicle ? DND had a whole batch of seal beams new in the box from GE that were bad , they came in the blue and yellow boxes , most did not work or blew almost instantly , other wise check your wiring , by the numbers, hope this helps,
Frank

[Stan Leschert]

Get out your multi meter, and check the bulbs first. Then start at the beginning of the circuit and keep going until you find where you have no power. Report back, and we might be able to tell you more, unless you find it yourself. Report back anyways.

[chris vickery]

I recently had an electrical issue with my 1970 CDN3.
I had no RH turn sig front or back. As I dove into it further I ended up with no sigs at all. It turned out to be two issues working with each other, like an electrical gang fight...
What I discovered after indepth diagnostics was that
1) the RH front sig wire was going to ground because of old insulation (shorting)
2) the sigs problems began in the turn signal switch. A NOS replacement cured the problem. These use a solid state board that was cooked.
As much as electrical issues are a headache, if you start with the basic and work from there it is usually not too hard to pin point the issue.
Break it down to individual components and circuits. A multi check on bulbs for continuity to ensure operating condition. A check on the circuit from point A to point B for continuity. Check your switch for operation on the high and low to ground. Check for connections being the correct ones as previously mentioned. NOS or new components are often times defective right from new.

[WayneR]

It turns out the number 18 wire has no continuity. I tried to by pass with a new wire but that didn't work either. Do I have to now change the entire wire harness or is there an easier fix?

Wayne