No dash lights after wiring project on W123 (not rheostat)

[glenn1179]

I was installing some aftermarket gauges in my 81 300td last night and managed to lose all of my dash, hazard, and climate control lights. I tapped into the hazard accesory light wire to light my new gauges. When I powered them up for a test everything died. The gear indicator light still works, but the rest are dead. I figured I just crossed a wire and blew fuse. I replaced the number 1 fuse and still no success. I ran a jumper wire from the battery from to the new gauges I installed and got lights at the new gauges, hazard, and climate control, but not the dash. My rheostat has been jumped. I pulled the cluster and checked the bulbs. I came here and did a search and found that there may be an inline fuse in the cluster in 86 and newer cars.

illumination bypass?

I was wondering if anyone found the same type of fuse in older model cars? I would go look myself, but I am at work and the car is in the shop at home.

Thanks,
Glenn

[whunter]

You will need to follow the power from the fuse, inch by inch to find the break.


Have a great day.

[glenn1179]

Well that sounds like a lot of work to follow all that wiring. That is why I was hoping for an inline fuse. Is there someplace that may be suspect to check first? I spent a lot of time staring under the dash last night looking for suspect wires, but saw nothing.

Thanks,
Glenn

[Pete Burton]

Don't know what vehicle you have but have you looked to see if the ground trace is burned through on your instrument cluster?

[glenn1179]

No, I haven't looked, nor do I really know what to look for. I am assuming one of the metallic looking traces on the board will appear to have a break that shouldn't be there?

Thanks,
Glenn

[glenn1179]

Good call on the burnt circuit board. I went home for lunch and took the cluster apart to find 2 burnt circuits. The only electronics repair shop in town is closed until April 2nd. I don't know how to solder electronics.

So, anyone think my fuel, oil pressure, and water temp board will work out of my 77 240d? How about a good tutorial on soldering electronics?

Thanks,
Glenn

[JWJ]

I have the same issue with the lights.

How did you remove the console to look at the circuit boards?

JWJ

[glenn1179]

First you need to remove just the gauge cluster. On the W123 this can be done just by pushing on it from behind. Gain access by removing the knee pad dash cover (underside of dash on the drivers side). Push out to gain access to disconnet the wires and whatnot that run to the gauge clusster. Then there is like 6 or 7 screws to disassemble the gauge cluster from the back side. The section with the oil pressure, temp and fuel level is the only one with printed circuits, but you need to remove all the sections to get to it. Once apart look for the burnt spots.

Pretty simple once you look at it.

Glenn

Edit: Just reread your post. The console (portion of the dash that runs between the seats) doesn't need to come out to check the circuit boards. If you are looking to check the wiring under the console, remove the ashtray and the 2 screw behind it that hold the support bracket. Then remove the rubber ring from the gear selector. The carefully pry up the plastic top cover piece for the console while sliding it towards the rear of the car. The electrical connections to the window switches and hazards will have to be unplugged before it can be take totally off.

[JWJ]

I understand and will be taking it apart this weekend.

I'll let you know what I find.

Thanks!