Dash light fuse blowing

[cfassett]

Hi all!

Got a question. Since I’ve had my ‘86 951, the fuse for the dash lights blows immediately when I turn on the headlights. The dummy lights all work fine. The issue is the fuse for the backlighting. Thought I had this fixed when I required the headlights, but was wrong.



Has anyone else had this issue? Wondering if there’s a common cause for this.

[944 Ecology]

What is the fuse number that is blowing? If you disconnect the instrument cluster, does the fuse continue to blow? Do you have a wiring diagram for your car?

[cfassett]

Originally Posted by 944 Ecology

What is the fuse number that is blowing? If you disconnect the instrument cluster, does the fuse continue to blow? Do you have a wiring diagram for your car?

Thanks for the guidance. This is fuse 38 “instrument lights.”

I disconnected the 2 cluster pigtails this morning, and it still popped when I turned the lights knob. Without the key in the ignition.

[cfassett]

Following this, also disconnected the pigtail to the headlight motor, and then the plug to the drivers headlight. Still popped each time.

[944 Ecology]

fuse 38 also feeds the license plate light.

[cfassett]

Originally Posted by 944 Ecology

fuse 38 also feeds the license plate light.

Interesting. When I bought this car, I recall the dash lights worked on the drive home. It also had one of those big aftermarket PORSCHE taillights, which I quickly pulled.

Found that on the license plate lights, one of the wires was grounded to the floor of the trunk. I cleaned up the wire connections on the lights and disconnected this wire from the ground and the fuse survived. Are the license plate lights supposed to have a ground like this?

[944 Ecology]

The brown wires are the ground for the license plate lights. The non-brown wires are not from the factory.

[cfassett]

Originally Posted by 944 Ecology

The brown wires are the ground for the license plate lights. The non-brown wires are not from the factory.

Thanks for your help! Had a positive wire connected straight to ground. Don’t ask me how it happened.

Crazy how I’ve struggled with this for almost a year, and with some help from NY, it seems that this issue was fixed in a few minutes this morning!

[944 Ecology]

It helps to have the factory workshop manual and the wiring diagrams.

[mytrplseven]

When I got my car back from having a complete disassembly and repaint, I had similar issues. I eventually had to disconnect all the exterior lights and found the reassemblers had not connected the side lights properly and was shorting everything to ground. Great paint job, though.