carat 3.6
MB Enthusiast
- Joined
- May 11, 2011
- Messages
- 4,034
- Location
- In the workshop
- Car
- S124 E300d wagon, W124 om606 monster, E46 v8 coupe
Hello all.
My daily runabout w124 e300 diesel estate, in which a fault is unheard of, has been playing up this week in a rather un-mercedes like way. The problem is electrical and is causing me a great deal of head scratching, the car is still in constant use so really needs sorting out. Below is a rough story of the problems.
Fault number one: With the car running, pushing the brake pedal cause's all dashboard instruments and gauges to stop working, and a buzzing sound comes from under the dashboard. Upon releasing the brake pedal, everything returns to normal.
I used the car for 2 days like this, but it then progressed that upon releasing the brake pedal the dashboard would not return to normal. It would only return after a breif rev of the engine, and I also noticed that the brake lights had stopped working. That afternoon I checked the car for anything obvious, but came to the conclusion that there was a short in the brake light wiring. Needing to use the car that evening, I temporily ran a new wire from the battery down to the brake light switch, and then to the brake lights at the back to get them working. I also disconnected the original brake light wiring just in case of a short.
This cured the problem till next day, when fault number 2 appeared! Now with the ignition on all the warning lights iluminate as normal but the bulb failure, low washer fluid, low coolant, low oil level, and low brake lining warning lights were dimmer than the rest. And they got dimmer and dimmer throughout the day everytime I started the car, till they can barely be seen.
Next morning I examined the wiring behind the dashboard, under the fusebox, and the fusebox itself. I couldnt see a problem, no blown fuse's or dodgy wires, so I decided the problem may be the light control unit. I swaped this for a known good unit and it made no difference to the problem, so I re-fitted the original back in the car, and this led to.......
Fault number three: Now the passengers side headlight has stopped working on dipped bean only! The bulb and the fuse are ok, but there is no power going to the light itself. Main beam and sidelights work as normal, and the bulb failiure light is now on constantly.
This needs sorting out before it gets out of hand! My only theory at the moment is that the light control unit has a bad earth? I wont have time to pull the car apart and check this till tuesday, so any ideas are most welcome.
If it develops another problem before tuesday I will post it here.
Any ideas guys??????????
My daily runabout w124 e300 diesel estate, in which a fault is unheard of, has been playing up this week in a rather un-mercedes like way. The problem is electrical and is causing me a great deal of head scratching, the car is still in constant use so really needs sorting out. Below is a rough story of the problems.
Fault number one: With the car running, pushing the brake pedal cause's all dashboard instruments and gauges to stop working, and a buzzing sound comes from under the dashboard. Upon releasing the brake pedal, everything returns to normal.
I used the car for 2 days like this, but it then progressed that upon releasing the brake pedal the dashboard would not return to normal. It would only return after a breif rev of the engine, and I also noticed that the brake lights had stopped working. That afternoon I checked the car for anything obvious, but came to the conclusion that there was a short in the brake light wiring. Needing to use the car that evening, I temporily ran a new wire from the battery down to the brake light switch, and then to the brake lights at the back to get them working. I also disconnected the original brake light wiring just in case of a short.
This cured the problem till next day, when fault number 2 appeared! Now with the ignition on all the warning lights iluminate as normal but the bulb failure, low washer fluid, low coolant, low oil level, and low brake lining warning lights were dimmer than the rest. And they got dimmer and dimmer throughout the day everytime I started the car, till they can barely be seen.
Next morning I examined the wiring behind the dashboard, under the fusebox, and the fusebox itself. I couldnt see a problem, no blown fuse's or dodgy wires, so I decided the problem may be the light control unit. I swaped this for a known good unit and it made no difference to the problem, so I re-fitted the original back in the car, and this led to.......
Fault number three: Now the passengers side headlight has stopped working on dipped bean only! The bulb and the fuse are ok, but there is no power going to the light itself. Main beam and sidelights work as normal, and the bulb failiure light is now on constantly.
This needs sorting out before it gets out of hand! My only theory at the moment is that the light control unit has a bad earth? I wont have time to pull the car apart and check this till tuesday, so any ideas are most welcome.
If it develops another problem before tuesday I will post it here.
Any ideas guys??????????
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