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Topic: Instrument Cluster Lights out (Read 1888 times) previous topic - next topic

Re: Instrument Cluster Lights out

Reply #15
hi everyone,

I dove back into this issue and I made a discovery: the headlight switch gets really hot. Like hot enough that the coil for the rheostat was glowing. I'm not a genius, but if its getting that hot, that means its pulling a lot of current. So guess i'll be ordering a new headlight switch.
The rheostat is the dimmer control. Drawing that much current, you should be blowing fuse 13 again.
Just turn the parking lights on. This will get the headlights out of the picture and still power the dimmer control.
Pull fuse 13. Does the rheostat still overheat?
If not, are you sure that fuse is only a 5 amp?

Re: Instrument Cluster Lights out

Reply #16
That'll help for the short term, but you should consider modifying the lighting system to have power for the LO-HI beams run through a couple relays, instead of through the switch.



They do! I have 2 relays mounted in the engine bay. They get signal from the headlight switch, and draw power directly from the positive terminal of the battery.
1986 Ford Thunderchicken, 5.0 AOD w/ Shift kit,  354,XXX miles. 1-Family owned. Original engine+trans.
8.8 Disc Rear w/ 3.73 Posi. CHE Control Arms. '04 Cobra brakes all around. 2000 Cobra R wheels. Tubular front LCA's. MM Steering Shaft. Unlocked Speedo, Lowering springs, Eibach sway bars front and rear. Ram air intake.

Re: Instrument Cluster Lights out

Reply #17
They do! I have 2 relays mounted in the engine bay. They get signal from the headlight switch, and draw power directly from the positive terminal of the battery.

Huh. Weird.
Long live the 4-eyes!  - '83 Tbird Turbo

Re: Instrument Cluster Lights out

Reply #18
I just started to have the same issue on mine. I replaced the headlight switch and the electronic cluster goes dim when the headlights turn on.
The electronic cluster is on full bright with the headlights off.
With the headlights on, it is adjustable with the dimmer control.
Sorry, my post wasn't very clear. What I meant to say was that my dash lights are doing the same thing. I replaced the switch thinking it was bad, but it is doing the same thing with the new switch, full bright with the headlights off and then goes dim when the headlights are turned on.

Re: Instrument Cluster Lights out

Reply #19
Does moving the dimmer thumbwheel change the brightness when the headlights are on?

Re: Instrument Cluster Lights out

Reply #20
Unfortunately not, when I turn the dimmer switch wheel the lights remain out.  It only happens when the headlights are turned on, when they are off the digital instrument cluster is fully lit.

Re: Instrument Cluster Lights out

Reply #21
Unfortunately not, when I turn the dimmer switch wheel the lights remain out.  It only happens when the headlights are turned on, when they are off the digital instrument cluster is fully lit.
Sorry, I thought when you said the cluster was dim you meant on but not bright.
If none of the dash lights up with parking lights or headlights on, check fuse 13.
See post 5 in this thread for the fuse panel diagram.

Re: Instrument Cluster Lights out

Reply #22
Update to my situation:
Bought a NOS headlight switch.

With the LED 194s in the cluster illumination, it will pop fuse 13 when I turn the parking lights on and/or the headlights.

When I put incandescent 194 bulbs in, the fuse doesnt blow, but the cluster doesnt light up with the headlights on. It still lights up with the key on.

Any thoughts? Could it be something in the cluster? Because the fuse doesnt pop with the headlights ON and when theres no bulbs in the illumination sockets.
1986 Ford Thunderchicken, 5.0 AOD w/ Shift kit,  354,XXX miles. 1-Family owned. Original engine+trans.
8.8 Disc Rear w/ 3.73 Posi. CHE Control Arms. '04 Cobra brakes all around. 2000 Cobra R wheels. Tubular front LCA's. MM Steering Shaft. Unlocked Speedo, Lowering springs, Eibach sway bars front and rear. Ram air intake.

Re: Instrument Cluster Lights out

Reply #23
1. Do you have a test light? If not get one.
2. Do any of the dash lights come on with the headlights/parking lights?

Re: Instrument Cluster Lights out

Reply #24
The fuses have two  test points that can be probed with a test light.
No power to either test point:  Problem is upstream from the fuse.
Power to just one test point:  Fuse is blown.
Power to both test points:   Problem is down stream from the fuse.

The test light probe is sharp enough to pierce the wire insulation for further testing.

 

Re: Instrument Cluster Lights out

Reply #25
1. Do you have a test light? If not get one.
2. Do any of the dash lights come on with the headlights/parking lights?

So I shouldve been more clear: When I turn the headlights ON: the cluster goes dark, the radio goes dark, and the climate control display goes dark too. And based on the wiring diagram you provided, they all share a ground?

With the headlights ON, the turn signal still lights up in the cluster. So does the High beam indicator.

1986 Ford Thunderchicken, 5.0 AOD w/ Shift kit,  354,XXX miles. 1-Family owned. Original engine+trans.
8.8 Disc Rear w/ 3.73 Posi. CHE Control Arms. '04 Cobra brakes all around. 2000 Cobra R wheels. Tubular front LCA's. MM Steering Shaft. Unlocked Speedo, Lowering springs, Eibach sway bars front and rear. Ram air intake.