Interesting - thank you. I've been assuming this was not the culprit because the light doesn't come on when I set the brake. The only time it comes on is when I turn the key and wait for the glow plug light to go out. Worth a shot though!
Mhmm. Interesting in return..
You also say it doesn't come on from the Reservoir switch on low fluid (or cap removed) either...
But it does randomly come on with no good reason..
So, probably you should first try to force it to correct operation:
The light gets positive current within the dash.
All those sensors on reservoir and lever are simple switches that provide negative (ground) (!) to the dash light, when engaged. (Wire colorcode is W-B White Black)
That means:
A) If you take off the connector from the switch (one by one) and simple bridge the contacts in it, the dasg light should come on. If it doesn't, there is either a ground issue from the connector towards the battery negative (W-B White-black cable) , or a connection issue from the other pin towards the light (R-W red-white cable in my BJ73).
You can rule out the first by metering the conductivity of thw W-B to ground on each switch. If that is ruled out and the switch and swimmer and stuff is also taken out of the game, only the connection towards the light can be faulty then.
B) If the light comes on occasionally and not properly triggered by the sensor switches, it must get a faulty ground (negative) from somwhere occasionally.
All in all I guess:
The R-W wires from both switches are supposed to join at or near the dash light towards the bulb's negative contact. (Unfortunately I have no clue where exactly that would be!) Probably those came off in that spot, causing neither of the switches to 'get to' the bulb any more, causing none of the sensors to work.
Probably there now is a loose, exposed end of cable on the bulb, which occasionally makes contact to the metal dash, and thus eliminates the bulb with no good reason.
My 2 cents
Good Luck. Gremlins are weired. Ralf
