Triumph Repair: guage display lights, triumph spitfire 1500, jumper wire

Question
I have a 1976 Triumph Spitfire 1500.  The lights in my guages barely illuminate the face.  At night I can barely see the numbers.  I checked that the ground wire was secure.  I pulled the bulbs and the bases, cleaned them and tested them.  They seeem to illuminate fine, but when installed the guages don't seem to light up.  I sprayed contact cleaner in the dimmer switch and it turns freely although it dosn't dim (off or on).  It gets really hot as well.  I can't imagine that it dosn't light up the face any better.

Answer
When the dimmer is in use the current goes through a resister to dim the lights. When the dimmer is in the "Off" position current goes direct to the lights. When current goes through a resister the resister heats up. When the dimmer is in the "Off" position there should be no heat at all. To test the resister just put a jumper across the two posts on the rheostat to bypass the resister. The lights should burn bright and no heat should be detected at the jumper wire. If your jumper wire heats up and the lights are still dim you have a partial short in the rheostat itself or in one of the instrument lights. If your map light and the parking lights are OK, then for sure the rheostat is at fault.
Let me know.
Howard