The red fuse sounds right, it should be right on top of the relay. I won't know for sure til I pull the car out of the garage and have a look. But, if the fuse is blown, replace it anyway and see.
Eli.

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'90 500SL (sold)
17" AMG's

How would you reccomend finding someone who is capable of doing this? Also where can I get the diagnostic computer?
Thanks

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Ben C. Simmons

Because of its age, you only need an LED and a 1K ohm resistor to perform diagnostics on a 1990 SL. Radio Shack sells an LED with the resistor built-in for less than $2. In the special case of the convertible top, you only need a paper clip or length of wire to diagnose.

Learn a lesson from this. Most newer cars abhor being boosted. You're lucky you didn't really fry something. In the future, charge the battery and then start the car on it's own. This takes quite a bit longer, but is much gentler on your electrical system.

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John Shellenberg
1998 C230 "Black Betty" 240K

http://img31.exs.cx/img31/4050/tophat6.gif

I am having a similar problem my car is a 300SL 1991 but I can not find a relay with a fuse opn top of it.My ABS light is on and the hard top won't unlatch for removal please help.

Can someone chime in?

The Overvoltage Protection Relay is in the compartment on the passenger side by the windshield which houses the fuel injection, ABS, and other modules it is pictured in this thread.

Well the OVR fuse solved 3 Problems for me.The hard top came right off and the ABS light is out and also I now have a MPG guage working properly.Thanks you all for your help.

Hello ELi

I have had the luxury of pursuing a number of running hot problems on a lot of M119,s of that ERA. Some times the obvious is not so obvious. In my many hours devoted to finding a solution to this problem I discovered something interesting. First and foremost, a fan clutch is designed to be influenced by the hot air that passes over the front of it. As the air temperature increases it will heat the bi-metal strip affixed to the front of the clutch. Once it is heated to a predetermined temperature the strip bends inward and pushes on a pin which causes the clutch to engage. Once the fan is engaged it draws more air through the radiator thereby extracting some of the heat from the engine.

Try this experiment, run your engine at about 2000 RPM and listen for a very audible “whirring noise” that your fan should produce once the fan clutch is engaged. You may notice that your electric fans will engage long before the fan clutch ever fully engages. In my many tests I was never able to get a fan clutch to fully engage in order to create that very audible whirring noise. The whirring noise was synonymous to MB fan clutches up until that point, so what changed?

Take a look at the position of your fan clutch in relation to your right side auxiliary fan. Notice the dome of the electric fan? The dome actually diverts the air which would normally flow directly to the front on the fan clutch around it. The fan clutch receives a minimal amount of hot air which is required for it to operate correctly. Hm! Call me crazy, call me wacky but it was the only thing that made some sense to me after numerous hours.

My remedy was to modify the blue two pole switch on the intake manifold so as to alter the electric fan operation. I recommend finding a repair facility, or somebody, around your area that has a resistance substitution box. You will need to experiment to find the best fit resistance value that will help the Aux fans to come on earlier. Voltage at the switch is roughly 1.35 for fan cut in and 1.75 for fan cutout.

I have another solution that I am experimenting with but the jury is still out on that one.

MrCjames,

Thanks for the insight, I actually sold the car a while ago. What helped my situation was new coolant mixed with about 60% water, and a couple of bottles of Water Wetter (maybe crazy but it helped a bit), and a lighter right foot on very hot days. I'll never understand the engineering behind all these fans that still allow the engine to run hot or overheat on some SLs.

Scott,

I can feel your relief, that little fuse almost gave me a heart attack at the time, glad it's fixed.

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'90 500SL (sold)
17" AMG's