Dash Lights

[67Doors]

For some reason my dash lights, flashers and brakes lights no longer work. I went ahead and replaced the printed circuit and cluster voltage regulator but still not working. Any ideas as to where else I should check?

[67Doors]

My Alternator and blinker lights are working.

[tbone6]

20 amp fuse would be my guess...

wiring-1967extlights02.jpg

[67Doors]

Thanks for the diagram. I replaced all the fuses and flashers but still no dice.

[67Doors]

What is also strange is that the wiring in this truck is from a 70. The gauge cluster and harness are from the 70. I also noticed that the heater switch lights are not working but worked before I plugged the gauge cluster back in.

[tbone6]

I had assumed your truck was a 67. What year and model is it?

[67Doors]

I had assumed your truck was a 67. What year and model is it?

It is a 67 but the dash is all wired like a 70 with a printed circuit on the gauge cluster. Guessing someone must have changed it out at some point. Looking through the diagram for 70 it's odd that I don't have brake lights because I don't see anything that ties the brake lights to the gauge cluster.

[tbone6]

Let's start with one at a time, easiest first. Do you have 12v dc power on the red wire at the brake switch? If yes, depress the brake and check for power out of the switch (red wire with black stripe).

[67Doors]

Let's start with one at a time, easiest first. Do you have 12v dc power on the red wire at the brake switch? If yes, depress the brake and check for power out of the switch (red wire with black stripe).

Thanks for the help, I will start at the brake light switch. Looks like the switch is powered through the Emergency Flasher which is powered by the 20 am fuse?

[tbone6]

Thanks for the help, I will start at the brake light switch. Looks like the switch is powered through the Emergency Flasher which is powered by the 20 am fuse?

It does not go through the flasher, but it does use the same hot wire as the flasher, which is powered by the 20a fuse.

[bluef250]

Check the rheostat on the light switch.

Turn switch all the way till it clicks both ways. One way is off. One way is on. Check to see if you have dash lights when in the on position. If you have lights, replace the light switch.

[67Doors]

Check the rheostat on the light switch.

Turn switch all the way till it clicks both ways. One way is off. One way is on. Check to see if you have dash lights when in the on position. If you have lights, replace the light switch.

I did try that as well and the lights never came on. I tested the break light switch and have 12v in and 12v out when the petal is pushed.

[tbone6]

Okay, I am going to assume that all the brake light bulbs are good...you did check them right?
Next we need to check for power at the turn signal switch. You can do this one of two ways;

1. If your turn signal switch connector is easily accessible, probe the red wire with black stripe while depressing the brake pedal. The connector can remain plugged in or disconnected for this.
2. If your turn signal connector is not accessible, disconnect the plug from the emergency flasher switch (it's easier to get to) and probe the red wire with black stripe while pushing the brake pedal. If you have power here then you will need to gain access to the turn signal connector anyway and go back to 1.

In both cases you should have 12v with the pedal down and zero volts with the pedal released.

If you have good voltage going to the turn signal switch, then we need to check voltage coming out. To do this the connector should be plugged in to the turn signal switch connector. You will need to probe the green wire and/or the yellow w/black stripe wire. They should both have 12v.

If no/low voltage then your turn signal switch is bad. Replacing the switch will get your brake lights working again, barring any additional problems.

Once we have your brake lights back we can move on to the next higher priority problem, which should probably be your flashers.

p.s. I prefer to use the power probe that has the bulb in it over the multimeter for these tests, the multimeter won't tell you if you have a current drop whereas the light will burn very dim if you do.

[67Doors]

Okay, I am going to assume that all the brake light bulbs are good...you did check them right?
Next we need to check for power at the turn signal switch. You can do this one of two ways;

1. If your turn signal switch connector is easily accessible, probe the red wire with black stripe while depressing the brake pedal. The connector can remain plugged in or disconnected for this.
2. If your turn signal connector is not accessible, disconnect the plug from the emergency flasher switch (it's easier to get to) and probe the red wire with black stripe while pushing the brake pedal. If you have power here then you will need to gain access to the turn signal connector anyway and go back to 1.

In both cases you should have 12v with the pedal down and zero volts with the pedal released.

If you have good voltage going to the turn signal switch, then we need to check voltage coming out. To do this the connector should be plugged in to the turn signal switch connector. You will need to probe the green wire and/or the yellow w/black stripe wire. They should both have 12v.

If no/low voltage then your turn signal switch is bad. Replacing the switch will get your brake lights working again, barring any additional problems.

Once we have your brake lights back we can move on to the next higher priority problem, which should probably be your flashers.

p.s. I prefer to use the power probe that has the bulb in it over the multimeter for these tests, the multimeter won't tell you if you have a current drop whereas the light will burn very dim if you do.

Thank you very much for your help. I was able to get to the connector. I tested red wire with a black stripe on the connector unplugged and I got 12v. Plugged the connector back up probed both sides of the plug and got nothing. Unplugged the connector and tested from the outside of the plug and got 12v. Left the probe in the same spot and plugged it back in and got nothing? Possible short some place?

Tested the green and yellow with a black stripe and I would get a max of 9v out of each when I turned on the blinker. Just to add some more fun my flashers started working since I unplugged the turn switch connector and plugged it back in.

[tbone6]

Ha! Good ol' electricity, always doing something you don't expect. It does sound like your switch may be shorted, but it also sounds like you have at least two different issues.

It sounds like a bad turn signal switch, but it could also be old crusty pins/sockets on the connector (see my comment on your flashers below). Pins are easy to clean off, just take a small wire brush and hit em with it, then some alcohol to clean off. Sockets not so much. What I usually do is get a small metal sharp object and scrape the insides of each socket as best I can. Then rinse with alcohol. You might also want to invest in some spray type dielectric grease. After you get everything cleaned up and working again hit all the contacts with a shot of the grease.

To check the turn signal switch, you can bypass the switch by putting a jumper wire from the red/black pin on the chassis side of the connector to either the green or the yellow/black of the same connector. This should light up either the right rear or left rear brake light if your wires going back are ok (don't forget to press the brake pedal when doing this stuff). If they do light up, then most likely a bad switch. If they don't light, first thing to do is check to make sure the ground is good at the light sockets. You should do this with a good meter, one that can measure in 0 to 100 ohm range.

You are trying to screw with me by getting the flashers to work, aren't you...
I think with the flashers working again, you probably have bad/loose connections. That is what makes me suggest you clean all the contacts, the rubbing of the pins when inserted into the sockets gives it a bit of a scrape, which may be enough to get them in contact again. You can also just try connecting/disconnecting the connector numerous times to scrape them a bit.