Ryan:

Knowledge is freedom! Glad to help.

Make sure you have Osram stop light bulbs. Don't, ever, use anything else except OEM MB bulbs. The CC grounds via the stop lamp filaments (and is disconnected when it loses its ground when the lamps are lit!) and the standard 1057 or whatever lamps don't have the correct resistance. Can prevent the CC from working, and will allegedly roast a good amp!

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

[QUOTE]Originally posted by psfred


"Make sure you have Osram stop light bulbs. Don't, ever, use anything else except OEM MB bulbs. The CC grounds via the stop lamp filaments (and is disconnected when it loses its ground when the lamps are lit!) and the standard 1057 or whatever lamps don't have the correct resistance. Can prevent the CC from working, and will allegedly roast a good amp!"


Fred,

This baffles me. The wattage of the buld is dependent on the resistance, thus e.g. all 10w bulbs should read the same. I f the resistance in the grouding theory holds true then any corosion, vibration or weak contact would also increase resistance no matter what bulb you used. Shurely the system is not that sensative or am I missing something?

I just visited the GDL website. There is a section of myths and misconceptions. They concur with my theory on brake light bulbs.

Steve:

Length, diameter, coiling, and specific resistance of the filament wire are all involved in making a lamp filament. I've not taken a really close look at the two lamps side by side, but I suspect that there is a difference in the filament diameter, if only because one is US made and the other isn't.

Wattage of a bulb is output, I think, not current draw -- European bulbs are usually marked in candlepower, not watts.

If there is a difference in induction effect (coiling and current flow), I could easily believe that low current draw ground will be different with different filament configurations. I would expect the CC not to work, but it is possible that excess current would cook it. After all, failed solder joints are the usual failure mode on these things, especially the main actuator ground.

I've heard from several sources that bulb type is important, including my indy mechanic who has "repaired" some cruise controls by using Osram bulbs.

Yes, a failed lamp or corroded socket will prevent the CC from working, too. Both filaments must be intact, and I think matched, although I don't know that for sure. At least well enough the lamp out warning doesn't come on.

Naturally, I could also be full of beans, too -- I've not experimented on purpose!

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

this is what i found on GLD online reguaring brake light bulbs. They basically say it's a myth. Who knows the truth, but here is the web page: http://www.gdl-online.com/bulb.html

Peter,
You wouldn't by chance have a schematic of the amp? I have a '76 model, 10 pin amp.

Steve

Sorry Steve, I don't.

I'm also not sure my indy mechanic does, either -- he has wiring diagrams, but that isn't quite the same.

Shouldn't be too hard to figure out if you have component descriptions.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

I found an excellent tech article for 77-90 cc at the MBCA site in their technical library,check it out.

__________________
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