I have been reading your tech forum as a guest and I can not believe how much knowledge you all have here. The wealth of information is astounding. So, I decided to join and hopefully bother you all with my problem )

I am in the process of bringing back an ’85 190E and have been mostly working on it on weekends due to work schedule. The car has 88k original miles and was parked for many years. It is now back on the road and runs ok. I am still going to replace the lower control arm, tie-rod & drag link, Idler arm (kit), etc. I bought them already; just need time to install them.

The main issue now is with both drive side windows not working after car has been running for a few minutes. It turns out that the reason is because of blown fuse #7. I could replace fuse 7 and both windows will start working. I can drive to the corner store, park and go in. By the time I get back out and drive the car, I’ll notice that the driver side windows have stopped working again. Yes, fuse #7 is blown again. Also, there is a 4 inches long wire that has a fuse in the middle and one end of the wire is attached to fuse #1 and the other end is attached to fuse #8. If I remove this wire, non of the windows will work. The glass 20amp fuse in the middle of this jumper wire was the one that blew every time. I did the jump with a wire that has no fuse and now the #7 fuse is the one that blows, leaving both windows on passenger side to continue operating.

I have no idea of what could be causing this fuse 7 to blow every time and not sure where to begin looking. I have tools and do all my own work on my cars but my knowledge of electrical troubleshooting is limited. Please help me get past this point and hopefully get to where this car is driven daily. Car is an ’85 AMG and looks exactly like this (same color and kit) but with factory fogs http://store.classicgarage.com/me190ewchpab.html

Benz repair shop owner looked at this car it last month and after looking the engine over mentioned that “this is Euro spec car”. Please help me. I have a multi-meter also.

Greg

MB wires the windows differently than you are describing.

FROM MB the left front & right rear are wired together. And the right front & left rear are on the same fuse.

SOUNDS like the electric windows have been added.

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There really shouldn't be a separate "glass fuse" from the factory, so it does appear that some after build tinkering has been done.

Thanks everyone for your input. You are right about after build tinkering in the past. The previous owner had 2 extra buttons/switch installed on that window switch plate next to the gear shift lever. I understand one was for the cooling fan activation. I guess his fan switch was bad or undependable so he wired it to where he can apply 12v directly to the magnet and activate the fan as needed. The car also had aftermarket alarm and stereo with amp. The person I bought it from had received the car (from the original owner) and decided to remove all the alarm and extra wirings because he believed that the alarm or something was preventing the car from starting. He said he took out a lot of wires pertaining to the alarm, etc. He was later able to get the car cranked and running. All this was before I got involved and took ownership of the car.

After removing the wires, he was applying voltage directly to the fan magnet via a wire jumped off the positive post of the battery. I have since replaced the fan switch with a new unit, filled the coolant, cranked the car and let the fan activate accordingly at a mark slightly past 80 on the temp gauge. I observed and confirmed that temp was holding steady at that mark and fan was automatically turning on and off as needed to maintain the temp at operating temperature. I returned to the car the next day and decided to flush the old coolant out and replace. I removed the lower radiator hose and let out all the coolant I could. I filled it back up and cranked the car. It idled until the temp went past the 100 degree mark and the fan never came on. After confirming that the fan should have been activated by now (based on the temp reading on the dash), I turned off the car and let it cool down until this coming weekend when I can get back on it. My suspicion is that the water level is low and needs topping up so the coolant can tough the fan switch and let the switch know how hot the coolant really is. I am suspecting that the coolant was low in the block due to the drain and fill I did at the radiator. I hope to locate the engine block drain plug this weekend and also drain and flush the block. Is my suspicion of why the fan didn’t come on this last time around even possible? With the sensor’s position on top of the head, is it not possible that a 2 inch drop in coolant level will leave the sensors dry and unable to determine an accurate condition of coolant temp? I need to locate the drain plug for the block.

I forgot to mention that the wires for the window switch are built like sparkplug wires and each one plugs unto its male counterpart (on the underside of the window switch) individually. So, you can unplug the wires one by one. They are not like 3 or 4 wires going into one connector and then that connector plugs unto the underside of the window switch. Is there a way to test the wires from the fuse box to the switch, etc.? I would like to confirm the routing of these wires so I can maybe trace them and see what I can find. Also, is there a way to test the R2 – Electric Window relay? I replaced it with a used spare but situation did not improve. I am really counting on help from this forum to resolve these issues, especially the window fuse. If I can find a car of same year in the Houston TX area, I would love to park side by side and compare wire routing, etc. Your response is highly appreciated, thanks. It’s almost weekend and time for me to touch the car again.

Greg

I found the reason for my window fuse blowing and causing both driver's side windows not to work. Remember how I mentioned that the wires for the window switch are built like sparkplug wires and each one plugs unto its male counterpart (on the underside of the window switch) individually, and you can unplug the wires one by one since they are not like 3 or 4 wires going into one connector and then that connector plugs unto the underside of the window switch? Well, I found similar car and noted which wire color goes to which pole. I got home and noticed that one of the brown wires was plugged on the wrong pole. I moved it to the center (cut off switch) where it belongs and the window has been working everytime without blowing the fuse anymore. Only issue to resolve now is that pressing the switch for window up results in window down, and pressing window down is actually window up. I just need to identify which two wires to move around. Unfortunately, the car I looked at was an '84 and mine is an '85. Wire colors were slightly different. Do you know which color to relocate?
I am still working on getting the coolant fan to come on when car is hot. I bought a Behr 2 prong sensor for $40 and installed it. I let car warm up from cold and when the magnet clicked and fan came on, temp on the dash was slightly past 80. I cut off car and let it cool down. The next day I cranked the car, i noticed that the dash temp reading was going close to 100. I checked and fan was not engaged. I let it get up to 110 and close to 120 before shutting down the car. I have tried a couple spare used fan switch and fan never comes on, regardless of temp displayed on the dash. I can unplug the 2 pin connector at the sensor, jumper both wires and get the fan to come on immediately. So the fault is with the sensors not closing and letting power reach the magnet. Since the sensor is non returnable, that's $40 down the drain. I have tried 4 used sensors and fan still don't get power. I will unplug the connector and check and each time, there is power on one side of the wire. Jump them and fan comes on right away. I am doing a flush and fill, then new sensor on the cold engine before cranking and let it get hot. Coolant level is fine since the low coolant sensor warns me when it is low. I would top it up and confirm that it is full before putting the cap back on and letting engine warm up to 105 or so before turning it off. I have collected one more sensor off a car in the salvage yard and will swap it in when I get home this evening. I hate to buy another $40 sensor I can't return. Does anyone know why the fan worked once on a new sensor and hasn't ever since? Where is the normal mark for the fan to come on? 80 is around the 8 o'clock mark. There is a 9 o'clock line around the 100 mark. The 120 mark is around the 10 o'clock mark. past that is the red line. I would expect a normal working sensor to come on and keep it around the 9 o'clock mark, right? Please help!

Greg

I swapped in the two used sensors I picked up from the salvage yard yesterday and now the fan comes on and keeps dash guage steady at slightly above the 80 mark. The sensors replaced were the 2 prong sensor that is front most on the head, and the 1 pin sensor that screws in on the side next to the distributor. I'll flush the engine one more time today then fill with 50/50 coolant. Hope to swap out rear suspension with a set of Koni this weekend (I already swapped front for a yellow Sport Bilstein), and hopefully swap in the lower control arms with ball-joints, tie-rod ends and idler arm bushings. Flush brake fluid and power steering fluid if time permits, run her through a car wash and then go for a 30 mile all out cruise. A/C is next, as well as a stereo upgrade. Then we'll get to the picture taking part very soon. Thanks everyone for your help in getting this beauty back on the road.