Hey guys so I'm having trouble figuring out why my gauge backlights won't work at night. The radio is not hooked up and I heard someone say that the radio needs to be hooked up for the cluster lights to work. None of the gauges work besides the speedometer. Other than that nothing works. I thought I needed to just buy new bulbs but I think these bulbs are good. Help plzzzz

 

do your running lights work?

 

Yes they do! But they will turn on and off after about 10 mins of being on.

 

your head light switch, may be messed up. have you checked all the fuses, dimmer switch?

 

About 50% of the time I have to replace the bulb holder to get the light to work. This is after trying a new bulb. Sometimes bending the contacts out on the holder is enough to get them working, as well as cleaning the contacts with fine sandpaper. Also, clean the contact area on the PC with a pencil eraser to clean it up. This is if the back of the cluster is solid, not crumbling. Many clusters are falling apart on back & can't be made to work again.

I rehab 10 or so clusters a year to resell. I took a truck end of the wire harness & rigged it so it will power all the lights on the cluster when plugged in. That way I can test them to make sure they all work before selling them. Much easier to troubleshoot it that way, on the bench rather than in a truck.

 

All Fuses are good. The dimmer switch? Where is that located? And the headlight switch, is that the switch that I use to turn the headlights on and off? You're saying that may be bad?

 

No F150's until '75.

 

It says f150 on it so it's whatever

 

If it's an F150, it cannot be a 1973 or 1974.

 

Well it's definitely a 73 lol and it says it's an f150

 

Who cares if it is a F100 or says F150, apples to oranges IMO. The guy needs help with his dash lights, not being told what truck he really has. In all actuality is does not matter. Unless there is a big difference in the headlight switch part #'s?

Radio power has nothing to do with the dash lights, is the headlight switch rotated full counter clockwise and just before the (turn on the dome light with the door closed notch)? Full counter clockwise is full bright on the dash lights.

scottscott is correct, fuses, contacts, headlight switch. Dimmer switch is or at least should be on the floor, just down from the ebrake pedal. NOT on the t/s switch like new cars and trucks....

 

Yes the dimmer switch works the actual headlight **** doesn't do anything when I turn it. The ceiling light is broke. So Wat could be the issue why my gauge lights aren't coming on? Bulbs don't look bad, also, when the headlights are on the will start to flicker on and off after about 10mins of use.

 

Rotating the head light switch is how you brighten and dim the dash lights, that is all. And rotating it counter clockwise is how you turn on the ceiling (dome or cab) light.

"Cab" light meaning the inside the cab one and not the CAB (outside on topof the cab) lights. But normally pulling it out to the 1st position is how you turn your park and cab outside lights, if you have them. With the flicker issue sounds like it is a bad headlight switch.

For the*dome*light*wire, hot-at-all-times power comes goes to the headlight switch as a GREEN with YELLOW stripe wire.*Dome*light*power comes back out as a BLACK with BLUE stripe wire. The same color scheme is used at the door jamb switches. BLACK with BLUE stripe runs out to the actual*dome*light. BLUE with a RED stripe is instrument panel illumination. It comes out of the headlight switch to the fuse box, leaves the fuse box again as the same color and is distributed throughout the dash.

There is no ground connection to the*dome*light*switches or the headlight switches. These switches switch power, not ground.
1) Make sure you have 12 volts on both sides of the courtesy lamp fuse. This circuit is hot at all times, so it doesn't make a difference what position the key is in. If you have power on only one side, replace the fuse. If you don't have power on either side, then there is other work to do first.

2) Pull the*dome*light*switches out and remove them. Make sure the terminal for the GREEN with YELLOW stripe wire in the connector has power.

3) Check the*dome*light*switches for continuity. With the plunger all the way out (switch CLOSED), the switch should be shorted. With the plunger pushed all the way in (switch OPEN), the switch should be open. If not, replace the switch.

4) With power to the switch proven to be good, and the switches proven to be good, the*dome*light*should*light*up. If the*dome*light*does not*light*up, remove the cover and check for power at the*dome*light*(not the side that's permanently grounded to sheetmetal) with the door OPEN. If you have power here, yet the bulb does not*light*up, replace the bulb.

This will prove out the door-side; if you get to the point that the doors turn the*light*on but the headlight switch will not, then we can cross that bridge.

 

It makes a big difference kiddo, because if it's a 1975, it would have an instrument cluster back made of a composition material that can TURN TO DUST before your very eyes!

1973/74's do not have this problem.

 

That is the answer I was looking for. This is out of a 79 Bronco...yea I took a cluster apart once.