Dim Headlights on 40:

[40ford]

Ok,I got my new headlight switch and it was in a vintique box?I noticed there was even a part number etched on it.Installed and I got 6.27 volts going in and 6.27 going out,problem solved here!Have not checked at dimmer switch yet.I did notice with lights on the connections for headlight pig tails on both sides get very hot!

[JSeery]

Originally Posted by 40ford

I did notice with lights on the connections for headlight pig tails on both sides get very hot!

Heat normally = resistance, so if they are getting very hot you would assume there is excessive resistance or current draw.

[40ford]

I checked the voltage at dimmer switch and don't have but about 4.50 volts.I am losing a lot of voltage from the headlight switch to the dimmer.I know the new switch is putting out 6.2 volt now?Would under the shell on firewall be the next place to check?Ok,I need to back track -I traced the wire from switch which has red markings on it(hot wire I guess)to the small box under dash where ballast resistor is and the red marked wire and a black hook up and with lights on they are "extremely hot" at small nut?Not sure what the purpose here is for???

[deuce_roadster]

There is a circuit breaker inside the square box with the holes in it to protect the wiring if there is a dead short. Perhaps that is the problem. The replacement is usually that whole piece of insulation board with the ballast resister and circuit breaker. When the circuit breaker is in action due to a short your headlights cut in and out.

[40ford]

I am really lost here.I am no electrical expert!I have 6.27 volt going in to switch.When I turn headlights on this drops to 4.21?Is this normal?

[marko39]

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Check battery voltage with lights on. You should have same voltage at switch and lights.

[aussie merc]

simply a bad connection is resistance and causes heat if any connection is hot its bad and needs to be looked at. 6volt systems suffer badly as it dosent take much resistance to eat up 6 volts if you need more help PM me

[40ford]

With headlights on car not running I have 6.06 volts at battery and 4.72 going into headlight switch?

[marko39]

What voltage do you have in and out of the circut breaker? Trying to find the culprit here.

[40ford]

which would be the in and out?Would that be the red marked wire going in?Is this with everything turned off?Ok,I checked the two post.With headlights off I have around 6 volts on both posts.With headlights on I have 6 volts at one and about 4.74 on other?

[JSeery]

Do you have a wiring diagram? The Yellow wire with the Red tracer is the wire from the Circuit Breaker to the Light Control Switch. The wire you are calling black is actually Black with a Blue tracer and it does from the Circuit Breaker to the interior Pillar Lights. The wire going into the Circuit Breaker should be solid Yellow and comes from the Starter Solenoid.

The Circuit Breaker should be opening up if there is excess current draw in the lighting circuit. It is possible that the points in there are stuck and keeping it from working or that it is providing excess resistance when there is a large current draw. Need to be careful, but you could connect a HEAVY gauge wire jumper between the two Circuit Breaker terminals and see if that fixes the issue. The problem here is that if the problem is not at the Circuit Breaker and you remove it from the circuit, there is no protection for the rest of the circuit wiring. So, you would only want the jumper on there long enough to check it out.

[TJ]

Among the good advice you are getting, have you checked all the connections to make sure they are clean and tight? Make sure all connections are clean and tight at the circuit breaker. Then check all of the bullet connectors at the headlights and tail lights. You are getting as lot of resistance(heat) which usually means loose and dirty connections. I suspect the dimmer switch as it's mounted on the floor where dirt and moisture can enter the contacts on the switch and cause corrosion. Also how old is you're wiring?

[40ford]

Originally Posted by JSeery

Do you have a wiring diagram? The Yellow wire with the Red tracer is the wire from the Circuit Breaker to the Light Control Switch. The wire you are calling black is actually Black with a Blue tracer and it does from the Circuit Breaker to the interior Pillar Lights. The wire going into the Circuit Breaker should be solid Yellow and comes from the Starter Solenoid.

The Circuit Breaker should be opening up if there is excess current draw in the lighting circuit. It is possible that the points in there are stuck and keeping it from working or that it is providing excess resistance when there is a large current draw. Need to be careful, but you could connect a HEAVY gauge wire jumper between the two Circuit Breaker terminals and see if that fixes the issue. The problem here is that if the problem is not at the Circuit Breaker and you remove it from the circuit, there is no protection for the rest of the circuit wiring. So, you would only want the jumper on there long enough to check it out.

I am afraid to do the jumper might create other issues.With headlights on at the breaker I have 6 volts coming in and 4.74 volts out if I am checking correctly?

[40ford]

Originally Posted by TJ

Among the good advice you are getting, have you checked all the connections to make sure they are clean and tight? Make sure all connections are clean and tight at the circuit breaker. Then check all of the bullet connectors at the headlights and tail lights. You are getting as lot of resistance(heat) which usually means loose and dirty connections. I suspect the dimmer switch as it's mounted on the floor where dirt and moisture can enter the contacts on the switch and cause corrosion. Also how old is you're wiring?

I have a new dimmer switch and not getting the voltage to it.Wiring does not look that bad,but I know that don't mean anything!Not sure if it is original or not.Car sat in shed for 25 years.

[JSeery]

Originally Posted by 40ford

I am afraid to do the jumper might create other issues.With headlights on at the breaker I have 6 volts coming in and 4.74 volts out if I am checking correctly?

If you have 6v into the CB and 4.74 out there is a major issue with the CB. You could try checking the resistance through the CB. But, IMO, you ether need to check it or replace it. Not sure how easy it is to find a NOS CB, but be careful about new parts that include the ballast resistor, most of the new ballast resistors are total junk.

[TJ]

I think before you go any further you should replace the wiring. You say it doesn't look that bad, what ever that means. If you are not sure about the condition or whether it is original or not I would opt for new harness.

[deuce_roadster]

Also, those stock bullet connecters can be pulled back a bit looking like they are connected but actually are not. There are a bunch of them under that metal wiring cover where all the wires come together. I would double check that all of them are indeed making a connection.

[40ford]

Maybe this is part of the problem.I don't think this is original wiring is it?This is going to my tail light.
IMG_1619.jpg

[TJ]

Looks like original wiring to me. If the rest of your wiring looks like that replace it.

[JSeery]

Looks like a replacement harness to me. They use an interwire with modern insulation covered with a cloth winding. The outer cloth covering is just decoration. The wires look fine. For appearance you could replace the wiring, but don't see how what is shown is an issue.