`76-240d electrical
 

I have a `76-240d, standard trans. . My problem is that when I step on The brake pedal, I lose all the elecrtical. (the gen. light and brake light go out) The same also happens when I turn on the headlights and sometimes when i jiggle the cigarette lighter!(the longer i hold the pedal down the longer the lights stay off after I release the pedal)If I can get the lights to remain on to heat the glow plugs, it goes out again when I give the final pull for the starter. A couple days ago I was told I had no taillights. One other odd thing has happened lately is that only the right headlight came on and the heater motor was runnig. then the heater motor cut out and the left headlight came back on. Since then, no heater motor. Is there a way to fix this besides a ful jerry can and a pack of matches?

Here's a thought...
 

Hi there,
I suggest you make sure that your battery terminals are clean and making a good connection. The best way to do this is to remove them and clean them with a wire brush tool made for the purpose, or one of the reaming tools. The other problems sound like they could be caused by a poor ground or grounds. Does your car have lots of rust? Make sure the engine to frame grounding strap is in good shape.

Richard Wooldridge
'82 300D/4.3L V6
Etc...

My 76 240D has had lots of bad grounds here and there.
The ones in the trunk, under the tail-lights were causing all kinds
of lighting and cluster issues. All I had to do was clean them with
a wire brush and retighten. All fixed.
Also check where the main battery neg cable connects to the body. The sheet metal on 114/115 cars tends to rust there badly.
I added an aux neg cable from my battery directly to the core support just in case.
Dr.D

still no love
 

checked the battery terminals and the engine to body ground strap.Everything looks fine there and now I can heat the plugs but when I pull the starter I lose power again. Power also goes out when I press the horn. Then I have to disconect and reconect the battery termional to be able to press the brake again.

continued...
 

Also I`m not sure where the grounds are under the tailights.I took a look but only saw the regular connections

the grounds should be brown wires, they will be grounded to the chassis , on my 81 240d the tail light ground wire is at the lower part of the light box in the trunk area, there are several ground wires behind the instument cluster, also make sure your fuse box contacts are clean and you upgrade to the copper tip fuses...

Your symptoms do indicate a high resistance connection. It could be on the ground or hot side of the circuit. There is less involved with multicircuit grounding as they all ground to the chassis or engine. The battery grounds to the frame and there is a heavy ground wire from the bellhousing to the frame to link it all up.

The power side goes from the battery to the starter and is extended first through a buss panel that should mount to the pass side frame rail. The large red (at one time) wires carry unfused power to the light switch and from there to the un-fused sections of the glow circuit and ignition switch.

Get a test light or volt meter and apply the load and follow this path untill you loose battery voltage. Check first at the battery pole, then the battery cable, then the starter terminal, then the philips screws on the buse bar, then the light switch, then the ignition switch.

From the other side ground should look like ground at the battery pole, then the terminal, then the frame, then the engine block.