Please Advise - Electrical Faults

[billmills1968]

I would be very grateful if you could give me the benefit of your thoughts on the following regarding my 1992 240gl saloon (1986 cc):

1) About 3 months ago the electric windows of both front doors ceased at the same time to work at all;

2) A couple of days ago when I went to start the car none of the warning lights on the instrument panel illuminated when I switched on the ignition.

The car started and ran normally, the indicators, horn, wipers and lights all worked, but when I drove it the speedometer and rev counter, fuel gauge and temperature gauge did not move.

The warning lights remained off but after about five minute driving the red battery warning light came on, as I was going along, and remained on. The battery is in excellent condition and fully charged, by the way.

I headed home, not wanting to get stranded.


My initial thoughts are: fuses, relays, shorts, bad connections and so on.

I'm a bit puzzled and thought I would ask your advice before I get stuck in!

The car only gets used once every three weeks or so, if that, and is kept outside.

Thanks in advance.

[rustytoba]

Firstly the easiest thing to check are the fuses, a common problem on 240s where the fuse holders become loose or corroded causing no end of gremlins. The fuse box cover clearly explains what fuse does what etc.

This may help with more than just the electric windows.

The battery warning light illuminates to warn of low output from the alternator, check that the thin wire at the back of the alternator has a secure and clean connection.

It is normally only used every few weeks and is kept outside, so you may have corroded slip rings in the alternator (usually only viewable with brush holder removed) once the alternator is off the engine it is easy to remove the brush holder (a hexagonal panel usually black plastic in appearance) normally 2 phillips head screws this will give access to the copper slip rings that can be cleaned with emory paper.

These may help I hope.

Scott

[billmills1968]

Thanks - some very useful pointers there.

[billmills1968]

Success!

I removed the old fuses and threw them away, cleaned the contacts in the fuse box with a brass wire brush in a Dremel, buffed and fitted new fuses and now I'm happy to say everything works.

Thanks for the useful tips.

[rustytoba]

Always glad to help, the 240 is a simple and reliable beast but all too quickly a few small problems can gang up on you.

Scott

[93240se]

I would probably disconnect the battery before cleaning up fuse holders with a brass wire brush! Never know what may short out if fuse holders still live.
Glad you got it sorted, 240 fuse holders notoriously dodgy, have you considered ceramic fuses rather than the plastic that give more trouble !
Regards, Richard.

[Nicholas Lewin]

Part of my annual service/check will be to at least look at the fuseboard. I've just cleaned mine up with Servisol (electrical switch lube/cleaner) and a hand brasswire brush and then a dab of Vaseline on the fuse-ends when putting them back in. All simply a pro-active approach to suspect 240 electrics!

Good luck!

[billmills1968]

Thanks for your replies rustytoba, 93240se and Nicholas.

I generally disconnect the battery prior to fiddling with any of the electrics and in any case to prevent current draining when not using the car - I only drive it once every 3 or 4 weeks.

When I reinstalled the fuses I used a tiny artist's paintbrush to coat the contacts with ACF50 which I have found to be pretty effective in keeping corrosion at bay.

Regarding ceramic versus plastic fuses, ceramic is hard to get hold of for all the required values. I bought "Durite" brand but I am not certain what they are made of. How heat resistant they are remains to be seen!

One reason why I like my 240gl so much is that it exudes quality. It's rather scruffy and scarred but the mechanicals seem to be in good shape. Most importantly, provided I put in the time, effort and a bit of money, I think I stand a fighting chance of being able to fix most of the problems that may arise.

Bill.

[AndrewBrown]

ACF-50 is a really good product,

most people will never have head of it though unless of course the have an aircraft.

the stuff acts like WD40 crossed with a waxoyl like "creep" which means it continues to spread into seems and folds and removes moisture like WD40

made specifically for the aircraft maintenance industry

I'm still impressed with it the down side is the price 4 litres is currently £99:19 at

[Derek UK]

http://www.ebay.co.uk/itm/like/26223...7338527&crdt=0