My instrument cluster lights will not light up! When I rotate the light switch dimmer control on the light switch, my instrument lights do not come on, but the interior doom light does. I have replaced the light switch, but this has had not effect on my issue.

My instrument turn signal lights work ok.

There are only three lights for this panel:
2 have wire colors are BLUE w/ RED Stripe
1 has wire color GREEN w/BLACK Stripe

I thought it might be instrument voltage regulator, but
my fuel, temperature and oil pressure gauges work ok.

Could it be a defective instrument regulator? If so is this on the back of the instrument cluster panel?

Is there an in line fuse link for this? If so where is it?

My Ammeter gauge doesn't move, so I am assuming at this point it is a faulty gauge.

I hope someone out there has faced this problem!

Thank you for your help?

Hal Kandes

 

what year is your truck?I belive the 67 through 71 or so was this plastic coated flat paper like wire on the back of the instrument cluster.It all runs into the hole where the plug for the wiring harness plugs into it.If you have this style what you need to do is quite simple.
first get sime emery cloth like sand paper and light sand the wires just to scuff a little
Second take a soldering iron and some eletrical solder and spread some solder on all the wires.Be very carefull not to burn the plastic insulator beside the wire or break the wire itself.
This tightens up the plug and makes contact with all the wires.
Good luck and take care.

 

Thanks for the reply!

Sorry about not stating the year. It is a 1969 F-250 camper special. It has the type of lights that have metal casing light socket and push into the metal panel (like 1965 -66 mustnags ) had a 1965 fastback.

The metal casing socket one wire running out of it.

Hal

 

I started my truck up tonight and was heading out to the gas station when I noticed my dash lights were not on. Headlights were on, dome light worked. I have driven it just a few times at night so far, but they had always worked before. Went on to the gas station and after getting gas the dash lights worked again. I had mentioned in another post my 2 right gauges (temp and oil) are out. Haven't checked it yet, but am thinking a bad ground for that one. Wound a bad ground cause dash lights to not always come on?

 

Yes, a bad ground would cause the lights not to work! If the lights go on and off radomly.

 

a couple weeks ago my dash lights went out, then my dome light. when i pulled the switch out the brass contact had broken off and the spring coil thing was seaperating from the insulator. it might be worth crawling under your dash to find out. i just realized you said you changed your switch. hmmm

 

I've had my dash lights go out before. Turns out to be the dimmer on the switch, would you believe it wears out in the spot it's sitting in? Try rotating the dimmer and pick a fresh spot.

Barry

 

When my dash lights went out, I changed the little bulbs. It's easier work if you take the instrument cluster out part way.

 

What size or type dash bulbs do these take? Mine is a 70, if there is a difference between the years. If anyone has the GE or Sylvania #, I'd appreciate it.

 

The bulb number is a 1895 (2 to 5 W).

I have used GE 57 with no problem.

 

I don't know what I was thinking!
I have been an aircraft maintenance test pilot for 20 years and I should have looked at this issue more closely first. THE GROUND!!!

On the back of the instrument cluster panel there is a main grounding wire. By first visual glance it looked fine, that's why I missed it! The ground wire is grounded with a sheet metal screw also attaching the instrument voltage regulator. This is where the problem lies. Some corrosion called dissimilar metal (usually a white powder substance) was between the ground wire and the instrument voltage regulator bracket.

Once I cleaned it off BINGO! THE LIGHTS CAME ON!

The way I isolated it was by running a separate ground wire and testing the system with a test light and ohm meter.

Hal

 

I think that your problem is going to be the printed circuit board on the back of the cluster. These wear out over time, and very hard to see any problems looking at one, unless you take the time to go over every circuit, uggghhh...........

A bad ground will do this as well.