Previous: Electrical 11: Connections Evolved looked at tools, techniques and wiring for electrical.
A few weeks ago I went to dinner in the Imperial. It was dark by the time we left, making this the first time to drive the car after dark. To my surprise I had no dash lights! Making matters worse the headlights were aimed sharply down, giving me about five feet of visibility (slight exaggeration). Good thing that it was a fairly short drive home on roads I knew well!
When the instrument panel was rebuilt the dash lights worked fine, so this was completely unexpected. I hadn’t done anything to the instrument panel!
Or had I…
When working on the HVAC controls I had discovered that the lighting panel was unplugged. So I plugged it in and it glowed. One problem solved! Or was it “one problem solved?”?
The most common failure mode on electroluminescent lighting is for the power pack to get weak, causing the dash lights to get dimmer and dimmer. The power pack produces 200 volts of alternating current. The capacitors in these power packs dry out over time, and the driver transistor can fail. The extra load of the HVAC panel could be enough to kill the lights.
Fortunately there are companies who rebuild the lighting power packs. Unfortunately this is fairly expensive and takes months. Even worse is the difficulty getting to the power pack: it is mounted high up on on the drivers side sidewall behind the kick panel. It is completely buried behind wiring, control cables, the emergency brake assembly, and the huge brake pedal bracket. It is a major effort to contort yourself under the dash to be able to even see part of it – I have no idea how to actually get it out! And back in… I suspect that this power pack was the very first thing installed inside the car and everything else was built around it.
There are some people making new replacement power packs – compatible modules made with new technology. These cost about half as much as a rebuilt original module and claim to work better. So I took a chance and ordered one from Ebay. If this didn’t work I could always pull the original power pack and have it rebuilt. Assuming I could figure out how to remove and re-install the old one…
When the new module showed up the first step was to test it. I unplugged the wiring from the old power pack and plugged it into the new module – fortunately the wiring was relatively accessible. Time to double check connections, turn off workshop lights, and turn on the headlights.
The instrument panel remained dark.
Not unexpected, so turn the dimmer control. And there was light! The instrument cluster illuminated just as it was supposed to. “And there was much rejoicing”.
With the new module working it was time to mount it. The new module is much smaller than the original, so there was no point in trying to mount it in the same place. There was plenty of space on the side panel for the new module, so it was simply a matter of choosing a location and drilling a hole for the mounting screws.
Hmm, while in there I might as well add some soundproofing. I had saved the larger scraps of Noico sound deadening material and used these to cover most of the sidewall. After this it was simply a matter of installing the new driver module, connecting it, checking that the instrument panel lights still worked, and re-installing the kick panel. One task down!
The headlight problem was simple. I had replaced original rear springs with heavy duty springs which raised the rear end. Raising the rear end makes the headlights point down. Fortunately headlights are adjustable: remove three screws in the headlight trim ring, turn the vertical adjustment screw until they are the proper height, and then reinstall the trim ring.
Now I just need to get out at night and check everything out!
Update
I got out at night and everything worked. Not quite as bright as I would like but usable.
Next electrical: Electrical 13: Relay That Window!
With the latest electrical gremlin under control it is time for something completely different in ProShaper.