Best discussion on electronics I've come across here in a LONG time. So, allow me to toss in a couple questions for the pros:

1 -- Get out on the Interstate and hit the brakes at speeds in excess of 70MPH in my SL. I get a slight pull to the right front and the ABS light comes on. After that it brakes w/o any pull. Turn the ignition off and the ABS light goes off. Got an ABS computer problem you think?

2 -- Just replaced the Environmental Control Unit (000 822 1203)awhile back ( a $1,500.00 part through Fast Lane and the MB dealership). Managed to find one on the internet for $125.00 so felt much better about doing it. Installed it and it worked fine for about six weeks. Now when I turn the A/C on and pull up to a stop light, the ECU makes a bzzzttt noise, the RPMs surge about 300RPM. You can put your hand on the ECU and feel this is where the relay(?) is sticking. So, the questions are: (1) what's causing me to continue to have this problem with the ECU, and (2) what's the connection between the ECU and the RPM surge? I'd think the latter would be more an idle control valve/unit problem and don't understand what's going on here.

FYI, I replaced the OVP at the same time I replaced the ECU. I've also replaced the idle control valve and idle control unit.

Any assistance here will be GREATLY appreciated.

__________________
Don
'85 500SL (Euro) - 186,000 w/a complete restoration and engine rebuild at 154,000
'95 C280 - 174,000