500 SEL electrical problems

I have Mercedes 500 SEL (1985). recently engine died on the road. Can not restart. Here is more details to the problem. 1. Fuel pump does not run with ignition key "ON". It does work when
connected directly (both wires). 2. Fuel pump relay MAKES A CLICK AT THE MOMENT WHEN NEGATIVE CABLE IS RECONNECTED TO THE BATTERY , with ignition key not in the lock (!?). 3. I found that ignition control module (Bosh) has inside burned resistor (R 24, which is mounted on the inside of the ICU box). For that reason the value on the reistor is unreadable. Anyway I found the detailed circuit for Volvo car with similar engine with value 310 kOm. After repair engine did not start anyway. 4. One more problem, .RADIO GOES ON ANY TIME I TRY TO TURN AN IGNITION KEY. 5. When cranking, distributor sends to the ICU signal about 1,5-3,0 V. Distributor cup and rotor are new. Ignition wires are new. Ignition coil was replaced a few Years ago. Fuel pump, fuel filter, fuel injectors are new. Battrey is brand new . Everything did work perfectly until now.
Does somebody have any idea if these problems are related to the possible short or ground in an ignition lock? I found that Volvo amateurs do this kind of repair almost routinely. Each separate component for ICU module cost abut 5 Dollars or less, ICU itself even used at least $115.00.
Thank you for any advice. A.N.
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Don't care whether it clicks or not. What is the date stamped on the side of the unit? It is the one cigarette box size with the word kickdown on it. If it is more than 10 years old, change it.
I would also check the overload relay... the one with red fuse on top. Check the fuse. If burnt, replace it.
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Wiring harness disintegration?
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me wrote:

Thank you for advice. I replaced the relay about 4 years ago. I check all fuses in the main fuse box, and two fuses which are closer to the front of the vehicle in separate housing. Wiring harness looks OK. Only unusual thing was water dripping sometimes after rain from the heating duct right under steering wheel. I also suspected ignition lock. Unfortunately I don't know how to get to the ignition lock. Do you know how? Thank you very much for your help. A.N.
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Mmm...I would jumper the fuel pump to run... I don't have manual handy now to tell you what pins to jump and try to start the car.
The overload relay fuse is the on on top of the relay... also located in your fuse box... it is a standard US ATO fuse... blade type. I would suspect the overload relay bad if you still can't start your car.
Wire is not an issue.
Ignition switch should not be an issue if you got all the dash lights come on as normally. Most of the time, when ignition switch goes bad, you have hard time getting the AC fan to come on.
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I'd sure suspect the ignition (key) switch - before anything else. Radio's actions make the key switch the top suspect, IMHO.
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