dead dash electrics 84 300SD
 

Hi just got into the car to start it and I have no lights at all on the dash brake glow plugs etc.... car starts then no tack oil pressure etc. checked fuses, under the hood and all are ok... strange... have not checked anything else.. are there any other fuses elsewhere??? hopeing someone can save me some time... thanks all Joe

it looks like everthing associated with the acc position of the switch is out...turn signals heater air ect.... is this possibly a relay I switced aroound the smaller ones however there is one large mettallic one.. dont know how to test... or maybe the ignition switch itself.. any ideas thanks Joe

Update... very strange to me .. I drove the car, and when the rpms are up the alternator light comes on... (car is charging however) the oil pessure gauge comes up slightly.. list of things not working.. speedometer, tach. turnsignals , a/c heater fan.. all istrument console gauges, glow plugs, again im thinking ignition switch... but does anyone know if it can be a relay or main fuse I dont know of. please help if you can.... joe

Jiggle your ignition key slightly after starting - does this have an effect on gauges or lights?

I already wiggled the wires.. nothing.... what do you think ignition switch????
I never had any problem before today

Joe, before my ignition switch went completely south on me - there were warning signs. Sometimes my gauges wouldn't work, other times the CCU would not operate. A slight wiggle of the key would usually restore the loss.....until one day:o

what is the CCU??? does this sound like an ignition switch??? Ive had no previous warnings... did you rr your new switch, how tough is it to do??? thanks Joe

CCU is climate control unit. Though, those things seem to be flaky in all the older MB's. That's why I love my 84 300D Euro.. manual controls! :)

Look in the fuse box.

There are two large 4mm red wires that run from the fuse box to the ignition switch. The enter the switch on pin 30.

See if you can verify that these two wires have 12V. If they do, then the ignition switch is the culprit.

If they do not, then there is a loose wire or corrosion between the battery and the fuse box.

Brian, These are the red wires w/o stripes, ive located them however, im off to the store to get a new VOM cant find the old one... assuming one of these red wires does not show 12 volts, is it fused anyhwhere that you know of Brian?? it seems like if the ignition switch is the culprit it would of had some warning signs.... thanks Brian

They are solid red wires........no stripes.........4mm diameter. If they do not have power, then the problem is not the ignition switch.

Report back with results.

Brian, I checkes the two red wires going into the switch..both have 12 vdc. So I guess I need a new switch, thanks alot Its great to know your not going to replace something you dont need. Well now the next question.. how hard to replace the switch. ive lookes at a couple threads but dont know if there talking about the whole thing tumbler and all. it appears from what I see there are 3 bolts which hold the electric switch on ... is is harder than just removing the 3 screws and switching parts???? again thanks Brian for all your help.. Joe

Just to be sure:

Turn the key to the #2 position (run).

Check for voltage at fuses #10, #12, #14 and #16.

If the switch is bad, there will be no voltage at these fuses.

No voltage at those fuses Brian......

Yep, afraid it's the switch.

Have not done it personally, so, can't advise. But, there are several threads on it, for sure.