[Kbehnke68]

Hi all, I installed a new wiring harness. With the headlight switch off I get 0 volts as intended. With the headlight switch on I get 12.5 volts on both the high and low beam wire. If I hit the high beam switch, this does not change and I still get 12.5 volts on both wires. It is a brand new switch from AAW. Is this supposed to happen? My headlights and marker lights do not work when the headlight switch is on. My windshield wipers work as intended.

 

[Everett#2390]

Either/or high/low beams, not both.
Dimmer switch on floor may be at fault

 

[Kbehnke68]

Either/or high/low beams, not both.
Dimmer switch on floor may be at fault

It’s a brand new switch. Maybe a factory defect?

 

[Kbehnke68]

It’s a brand new switch. Maybe a factory defect?

i just tested my other dimmer switch that worked before I out the new one in. Same thing. 12V on both high and low beam wires. I tested the wires that go to the dimmer switch. All 3 are 12.5 volts with headlights on (yellow, brown, green) and not energized with headlights off. What am I missing here??

 

[SOA-Nova]

Try disconnecting both headlights and retest at the dimmer switch.

Also maybe disconnect the wiring plug on the dimmer switch and test the switch itself using your meter set on ohms or continuity.

Jim

 

[scblucam]

The old dimmer switches are notorious for grounding to the floor if stomped too hard. Pull the connection off of the floorboard. Under the carpet.

 

[R66]

Correct me if I am wrong. The dimmer switch receives power (12vdc) from the light switch, I think it is the light blue wire. In one position, it sends power to the dim lights so that terminal becomes hot (12vdc) but the other terminal, may be the light green wire. In the other position, it sends power to both the dim and the bright lights, the brights may be the tan wire. The dimmer switch is a push button switch and the contacts inside determine what is powered - only the light green wire or both the light green and tan wires.
A dimmer switch can fail in either position. You can test it with your VOM meter.

 

[SOA-Nova]

I have two wiring harness that have original floor dimmer switches on them. One is from a 66 Malibu and the other from a 74 Nova.

I tested both switches with a meter and the top terminal is where power comes into the switch (and on both original harness this wire is blue) and then gets directed to either one of the lower output terminals (which on both harness.the green was the high beam output and the tan the low beam output).

If I put my meter across the top terminal and one of the bottom terminals I showed no connection but then moved my meter lead to the other bottom terminal and I showed a connection.

I then pushed the dimmer switch fully down to get it to click over and let the switch plunger come back up.

I then tested between the top terminal and the one bottom terminal that showed connection and now it showed no connection but now the other terminal showed connection.

I then also put my meter across the lower output terminals and they show no connection to each other and then verified that when the switch was pushed down and clicked over and released, these same two bottom output terminals still showed no connection to each other.

Here are the results of a switch I tested (Out of a 74 Nova and then had the same results with a original switch out of a 66 Malibu):

If your test results match on the left side of the above photo, then one click down and releasing of the switch should produce the test results on the right side of the above photo.

Basically the above switch is connecting power to either the low beam output OR the high beam but never both.

Years ago I took a switch apart and this was what was inside:

Chevrolet Floor Headlight Dimmer Switch

Explore this photo album by Stlnovas Streib on Flickr!

www.flickr.com

If for some reason there is a short internally of the switch to the floor, then the power coming out of the indash headlight switch will go to that short and then either open up an internal circuit breaker on some headlights switches or it may blow a fusible link.

Jim

 

[Kbehnke68]

I have two wiring harness that have original floor dimmer switches on them. One is from a 66 Malibu and the other from a 74 Nova.

I tested both switches with a meter and the top terminal is where power comes into the switch (and on both original harness this wire is blue) and then gets directed to either one of the lower output terminals (which on both harness.the green was the high beam output and the tan the low beam output).

If I put my meter across the top terminal and one of the bottom terminals I showed no connection but then moved my meter lead to the other bottom terminal and I showed a connection.

I then pushed the dimmer switch fully down to get it to click over and let the switch plunger come back up.

I then tested between the top terminal and the one bottom terminal that showed connection and now it showed no connection but now the other terminal showed connection.

I then also put my meter across the lower output terminals and they show no connection to each other and then verified that when the switch was pushed down and clicked over and released, these same two bottom output terminals still showed no connection to each other.

Here are the results of a switch I tested (Out of a 74 Nova and then had the same results with a original switch out of a 66 Malibu):

View attachment 298565

If your test results match on the left side of the above photo, then one click down and releasing of the switch should produce the test results on the right side of the above photo.

Basically the above switch is connecting power to either the low beam output OR the high beam but never both.

Years ago I took a switch apart and this was what was inside:

Chevrolet Floor Headlight Dimmer Switch

Explore this photo album by Stlnovas Streib on Flickr!

www.flickr.com

If for some reason there is a short internally of the switch to the floor, then the power coming out of the indash headlight switch will go to that short and then either open up an internal circuit breaker on some headlights switches or it may blow a fusible link.

Jim

Appreciate the detailed response. Hoping to get some time to work on the car next week. Will let you know how I make out.

 

[SOA-Nova]

Appreciate the detailed response. Hoping to get some time to work on the car next week. Will let you know how I make out.

There is a lot of bad info and good info out there and hopefully what I've offered helps or gives you some direction.

Please do respond back with that you find out as this can not only close out this thread but possibly help others down the road.

Go ahead and be detailed with your findings. We love that stuff.

Jim.

 

[Kbehnke68]

There is a lot of bad info and good info out there and hopefully what I've offered helps or gives you some direction.

Please do respond back with that you find out as this can not only close out this thread but possibly help others down the road.

Go ahead and be detailed with your findings. We love that stuff.

Jim.

Hi all,

so another easy fix that I overcomplicated. One of my headlight bulbs and one of my marker lights were Broken even though they looked to be intact and worked fine the last time I started the car. New headlight went in and The car worked.

however, the passenger side bulb is significantly dimmer than the driver side bulb. My local auto parts store said that they he 6014 bulbs were discontinued and said I could install an H6024 as a replacement. Is this correct and it’s just a wiring issue? Or are do these bulbs pull too much power and this both sides of the headlight aren’t getting enough?

 

[Kbehnke68]

Also, while I assumed turn signal lights were grounded at the housing, that’s not the case. When I grounded them with my power probe they functioned properly so I have to run a jumper wire from the signal housings to the radiator core support for ground.

 

[SOA-Nova]

Hi all,

so another easy fix that I overcomplicated. One of my headlight bulbs and one of my marker lights were Broken even though they looked to be intact and worked fine the last time I started the car. New headlight went in and The car worked.

however, the passenger side bulb is significantly dimmer than the driver side bulb. My local auto parts store said that they he 6014 bulbs were discontinued and said I could install an H6024 as a replacement. Is this correct and it’s just a wiring issue? Or are do these bulbs pull too much power and this both sides of the headlight aren’t getting enough?

It's possible the different brightness may be from different model bulbs.

Ideally replace them in pairs.

If with a matched pair of bulbs the brightness is different between the two, then maybe it's a connection issue at the bulb or even a ground issue. If it's been that way from day one and never been right, maybe someone changed some wiring on the car and that is not right.

Jim

 

[blm]

My local auto parts store said that they he 6014 bulbs were discontinued and said I could install an H6024 as a replacement.

Just a suggestion. You might consider changing those plastic AAW headlight sockets. Those Halogen bulbs get pretty hot. Maybe a ceramic socket that is not in danger of melting.