Well, as it goes with old cars, things are never easy...
After messing with the dash last week and feeling pretty confident I had it's issues solved, I was excited to try it in the car on Saturday, so braving the wind and iffy temperatures I went to the car, plugged it all back in and....same B.S.
Pull out the wiring/pin out diagrams for the car and spent an hour or so checking the harness in the car....found and fixed one bad ground, but still no dice with the dash. Then I was able to position the cluster so I could remove the back cover while still plugged into the car, and spent another half hour checking circuits....again, no luck.
I did get the blower motor working for $0 (bad ground), fixed a power window switch that was all loose in it's socket, and replaced some exterior bulbs to get all the lighting working properly. So not a total loss of the afternoon, but the inoperable dash kind a put a damper on it.
I was pretty well done playing with the dash, so I went online looking for refurbishers I could send it out too....All US based, and pretty $$, but I've gotta have guages.
Sleeping on it though, I decided to take another angle today. I spent another hour or two making a bench test harness....Basically identifying all the pins I'd need to put 12V or ground to in order to get it to power up. Of the ~50 pins on the thing, most of them are information inputs from the car's sensors, some cruise control circuity, etc. I figured that there were 3 pins that needed 12V and 2 that needed ground to get it to fire up (without any info to display obviously). I had some tiny female pin terminals (left over from DTS heated/cooled eat module repair years ago) and used those and some random scrap wire to build a little harness.
Plugged into a battery on the bench, it behaved exactly as it did in the car.....So at least that ruled out any of the car's wiring as an issue. With it open on the bench, and powered up, I could really poke around inside and start checking outputs at capacitors and w/e to follow the flow of power. Doing that, it didn't take long to find where the voltage dropped off, and investigating around there I found a spot where the 'power supply board' wasn't making a proper connection to the main board. Manually making the connection (by pushing on it) the dash would light op properly! Cleaned up that connection and built a little clip (from a cable staple) which I combined with a bit of superglue to hold the power board in place properly.
And she works!
Here it is, hooked up an in 'self test mode' (first 5 seconds or so when it powers up and everything lights up):
And here it is in 'run' mode...Course, there's no data because none of the input feeds are hooked up.
The brightness is very sensitive, there's a little light sensor in the top left corner and if I shut the lights in my workshop off it dims right down, turning the lights on and shining a flashligt into the sensor, it goes full bright. Pretty cool.
Anyway, the trials of cars like this....it's so frustrating when you're losing, but feels so good when you finally beat it. Since I got the dash fixed with zero $ spent, I am gunna order up some weather striping and window sweeps
