I have a '78 124 Spyder and I just replaced altenator. While altenator was being rebuilt I was messing around with the tail light assembly, checking bulbs and wire connections. I installed altenator, connected wires and it works great. Now instument cluster does not work. only speedo works. No tach, fuel or temp. Also, no back-up lights or brake lights. Tail lights and blinkers work fine, checked ground and wire connections, seem to be OK.

three major but vague suggestions in reply. providing all your gauges worked before you started... and providing you did no work on the gauge cluster...

1. always go back to the last thing you did and triple check the connections.
2. always suspect faulty ground connections.
3. never attempt to work on multiple electrical circuits at the same time. you will only frustrate yourself through confusion.

Thanks for the input. I did find out that the problem was nowhere near where I was working. It was with the fuse panel. I traced all the non-working items to one fuse which seemed to be working. With a little checking and testing the system began to work again. So either it is with the fuse or maybe the ignition switch, which I kept turning on and off to test the fuses.

fuse panel:
1. disconnect the neg battery cable
2. remove all fuses and discard
3. clean the fuse contacts with 00 steel wool, pinch the contacts closer together for a firm fuse fit
4. replace all fuses with new fuses of the correct amperage
5. reconnect the neg battery cable

install a secondary grounding cable between the engine block and the body.

the large white multi wire connector behind the ignition switch is prone to failures. disconnect, clean, and tighten all of those connections.