Issue with circuit #1

[leeputmanjr]

In my '78 131 Wagon, the fuse #1 circuit has some intermittent issue where the whole circuit goes dead. 

This circuit involves the fuel gauge, starter interlock (for the automatic transmission), the ignition relay, reverse lights, heater fan, and so on.

I have swapped the starter relay, and bypassed the interlock on the auto-trans, all to no avail.

Has anyone else seen this issue, or have any idea where a problematic area is on this circuit?

Thanks!

-Lee

[Thotos]

I'd guess that if the whole circuit goes dead, the problem is with the fuse box. It's relatively common for the spade connector pins to get a bad joint onto the printed circuit 'board' which is not a real board but a cellophane type flexible board with copper tracks. 

[TOAD]

Does the engine cut out?

[leeputmanjr]

No - the engine will continue to run - but then it can't be re-started!

[david]

As mentioned previously take the fuse box out and unscrew it and clean up the related terminals inside as I have had troubles there with headlights etc and this was one of the reasons for it.
Also check the brown wire where it joins to the ignition switch in the block as these are always burnt to some degree but if it was really bad you should have an electrical burning smell and usually the engine will cut out but not always.