A quick test for the low speed fan operation is to unplug the LS relay from the socket inside the fuse box. Get a gauge 18 stranded wire. Strip the insulation on both ends about 1/4 inch long to expose the copper strands. Insert one end on the relay socket at terminal 85. This bypasses the ecu and the radiator temperature switch. Reinstall the low speed relay on the socket. Turn the ignition switch to ON but do not start. Ground the other end of the jumper wire. The fan should run in low speed. If it does not, the low speed resistor in the fan is blown or open.

Considering I have a new sensor switch and HS relay, I am going to disconnect the Sensor switch, and also the plug from the fan.

In theory (right), if I jump either the LS or HS side of the sensor female plug, I should get power to the fan plug itself. That should take me to the route of either the issue is between the loop, or to the fan itself. (Possibly bad diode or resistor to the LS fan section).

But this should, I say should, eliminate the fan one way or the other.

Replaced my HS relay today and after getting it up to temp the low speed fan kicked on while it idled. My thanks to all the people who posted the great info in this thread.

Sweet! I just placed an order for a high speed relay today. $12.19 + $0.89 tax. I'll post my results too.

My issue appears to be the radiator temp sensor. At the plug, doing the test on Page 170-5 of the Bentley manual, I can jumper Black/Green + Brown and get Low fan speed. Jumpering Black/Grey + Brown turns the fan on High. It works with both my old high-speed relay and the new one.

That's what I get for not doing my research and the proper diagnosis first! ;)

DIY: Pre-fan delete mod: auxiliary fan circuit testing
 

Well! Here's my write up that might relate to this topic, I guess. http://r18.imgfast.net/users/1812/10...les/672707.gif

http://forums.bimmerforums.com/forum....php?t=1679680

that's pretty much the very first thing anyone should verify before going through the trouble of testing the relays and ECU inputs.

If it does not pass the sensor test, proceed to testing the relay interlocks and control circuit, then the ECU input.

Just so you know, people don't usually delete their electric fans. The FDM is more for the 328/M3 with the engine driven fan/fan clutch.

Very good info though and good to see pictures showing the procedure.

:rolleyes: my pleasure http://r18.imgfast.net/users/1812/10...les/672707.gif

+ I have learned more that the HS fan runs on the A/C in m44 radiator mount fan from this thread in which differ from my 94' m42 front mount fan that runs LS on A/C operation though. So, I need to do some wiring conversion under the fuse box board on my m44 fan conversion project. :cool:

Why the roll eyes? Maybe there is something I don't understand? I wasn't aware that people deleted the electric fan on the M42/44.

I mean I am referring to all the above postings, easy mate http://r18.imgfast.net/users/1812/10...les/672707.gif

Sorry, rereading my post it could come off sounding wrong. I didn't mean for it to sound that way. No worries.

Removing the fan on an M42/M44 equipped car is not a good idea AT ALL. These engines are much more prone to overheating than M50, M52, S50 and S52 engines. 9G3Series, your car is a 318i. The 318i has both a "pusher" fan (mounted in front of the radiator) and a "puller" fan (mounted behind the radiator). The 318ti only has a "puller" fan which operates in two modes. Low speed intermittent cools the radiator when the coolant reaches a certain temperature and high speed constant when the A/C is turned on. Furthermore, the 318ti does not have the clutch driven fan mounted on the water pump pulley like other e36's do. So it's imperative that the puller fan remain installed and function properly as it's the only way to cool the engine when the car is sitting at idle or the a/c is turned on.

I'm sorry, but your writeup is not relevant to 99% of the members on this forum and may possibly mislead someone into removing a critical part of the car's cooling system. I'll finish by saying that the FDM was intended for cars equipped with a clutch driven fan. This is the fan that is attached to the waterpump on the front of the engine. Again, 318ti's don't have this fan. The reason people remove this fan is because the plastic blades are known to break off and cause MAJOR damage. I've seen cases where the blades have dented hoods, destroyed radiators, caused belts to pop off etc. In some cases, people didn't even know their fan was missing blades, meanwhile the fan was unbalanced and causing excessive wear on the water pump bearings. If you google "e36 exploding fan" you'll see what I'm refering to. The only reason anyone would consider doing this mod on a 318ti is if they've done an engine swap and have a 6cyl engine with a clutch driven fan. FWIW, I plan on keeping my clutch driven fan on my S52:wink:

Well, you are exactly right to make it an elaborately clear explanation. However, my write-up is in the another social not in here, 318ti.org, though.

But thank you anyway :wink:

So just a FYI - 96 M44 HS Fan relay is part no: 61361388911 found in fuse box NOT under dash.