A friend of mine has got a 1971 Imperial Lebaron and no gauges except for the speedometer are working - mechanic tried to fix them, but he can't seem to make them work together with sensors.

Does anyone here have some experience repairing these things? Is it possible to get replacement electronics for the gauges or fix it, or is it better just to slap a few autometer gauges under the dash?

Here's a link to wiring diagrams that might help. http://www.mymopar.com/index.php?pid=27

Used I.P.'s a/o guages are always are popping up for sale.
My experience is that you're better off going that route.

My 72 Imperial has the same problem. Only the speedo and oil pressure gauge work. Even the clock is dead.
I think it's a voltage limiter thing. I haven't worried too much about it since mine isn't really a driver yet. I do have the factory manuals and will run down the problem when I rebuild the car.

Most of these cars (of the late 60's-Early 70's) had electronic circuit boards that were not well protected. They generally crack/warp/become powdery and just flat-out fail after 30+ years.
I've seen MANY a B-Body with the rally cluster that the board was just toast. The only real 'fix' is to find a replacement board, or use solder to jump the cracks in the circuitry.
The board is the first place I'd look though.

Good luck with it.

CC.

I probally have a few complete dashes in the garage.I pulled them when I scrapped my Imps.They signal sentrys even worked as did the hard to find switches.Typically if one gauge works the limiter is good.69 to I believe 71 or 72 all used the same dashes.Rocky