I am towards the end of installing/testing the new 'Painless' wiring on my '66. So far, not too bad. I do have one remaining issue that I am stumped with and looking to see of there is any suggestions out there.

The headlights only have high beam, but not low. I have replaced the dimmer switch with a known working one and still nothing. I have power going into the switch but nothing coming out. Again, I changed out the dimmer switch to see if that was the problem and nothing. Only getting high beam... Any ideas?

 

Jump the dimmer power lead to one, then the other, of the headlamp feeds, and see if they work. If they do, you know the switch is the culprit.

 

So jump it at the dimmer switch? So I understand, take a jumper wire and attach to low then high, correct?

 

Yup. .

 

Ok - this rookie electrician needs some help.

Here is what I just tested:

I took a test light and checked B+ at the dimmer switch and it was hot. Good. We have power to the dimmer switch.

I turned on the high beams and checked for power at the high beam wire. Checked good and high beams turned on.

I turned on the low beams, no visual light. Used the test light and nothing. No power.

I did the suggestion next from 2+2. I took a jumper wire and touched one end to B+ and the other end to the low beam and got a large spark and pop so I stopped.

Suggestions?

 

Sounds like you have a short in the low beam side.

 

same opinion here. there's something wrong between the switch and the connector at low beam (or the connector at low beam on other lamp)

 

If you got a spark on the low beam terminal of the dimmer switch, power from the battery to the switch is "wired", your problem would likely be from the switch to the headlights.
If you suspect the dimmer switch, Take the switch out of the circuit if you know which wires power the low beam. Disconnect the battery.. Make a jumper wire that will hard-wire/jump the low beam at the hi-beam switch's wiring harness. Make sure the wires are not loose or you will get another "pop" from the bad connection. Then re-connect the battery and turn on the headlights. If you have the low beam, you know the problem is the switch or a loose connection at the switch.
Since you are re-wiring the entire thing, I would check the connections at the headlight switch, the headlights (check ground)and if possible follow the harness and make sure ALL the connections are tight. You may have a blown fuse, check the fuse box, fuses in the headlight switch and of course there are circuit breakers in the dimmer switch that you re-set by pressing the button. You should unplug ALL the connectors to the switches and the headlights and inspect them and plug them back in, may have a bent or misaligned terminal that is not making contact.
is there any grounding that may not have been reconnected to the headlights? Any hardware that you think is unrelated to the electrical that may be part of the grounding circuit (could be as simple as a single mounting screw.)
The last thing I might check is to examine the old dimmer switch wiring and make sure the wire colors match up in the same position as the new harness. It could be possible one wire is not correct to the old harness.. it does happen for any number of reasons.
If none of this helps, do you have a voltage meter or a self powered test light (light bulb, battery and some wire)? Disconnect car's battery power, test from the low beam headlight terminals back toward the light switch then the dimmer switch, it will help isolate where the problem lies. If the light comes on or positive voltage meter reading (continuity setting), that section is good, just go back connector by connector, once you don't get a "signal", the bad connection/switch is between the last good reading and the point you are at when you lost the good reading.

 

Ed - great advice, I appreciate it. Let the troubleshooting begin!

I guess for replacing the car's entire wiring this is the only issue so far, can't beat that.

 

Here is what I know.

The B+ coming from the headlight switch on the dash is hot, providing power to the dimmer switch.

The High Beam works on the dimmer. No power to Low Beams.

No power on low beams exiting the firewall from the dimmer switch.

A known good dimmer switch makes no difference.

Only thing it can be to me is the actual dimmer switch harness. Is that possible?

Am I missing anything else?