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Discussion Starter · #1 ·
I know this topic has been run into the ground but I have not been able to find some crucial info I need to finish this little project. I know this is simple but I need a little push. The controller I have is a 3635 Hayden adjustable. It is rated at 16 amps / 250V. The pusher fan this will be controlling is a Hayden 3700 1400cfm that pulls 16.5 amps. Can I tap an unused location in the fuse box (power seat controls) for this controller? The space is unused and is rated at 30 amps. If this is OK to do, what is the correct way to tap the unused space? I am 99% sure this is not continuous 12v but I have not co firmed with my multimeter. As I said, I want to do this the right way. How can I integrate a 30 amp relay into the space correctly ( or do I need to do this?)? I planned on using an inline fuse as well- in addition to the relay. Am I going about this the right way or am I way off base. I searched the forums and I couldn't find anything that directly addresses my situation. Any help would be greatly appreciated. I hope I am using this forum correctly. I posted another question and 60 people viewed it but no answers. I really want to know what I'm doing with this and I want to do this the right way. This situation has me grounded until I figure out this little dilemma. Any help is greatly appreciated. One last thing- of course I wish I had the money for a SPAL and a good controller but this is what I have to work with right now so I have to make it work- and I live in South Florida so things can get a bit warm here. Thanks again... Here are links to what I have to work with:

Hayden Automotive 3700 - Hayden Electric Fans - Overview - SummitRacing.com

Hayden Automotive 3653 - Hayden Electric Fan Controls - Overview - SummitRacing.com
 

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I'm not sure why you're not installing the fan as its OEM. Also, using the slot for power seats will most likely be key switched; the fan will not be able to switch on with the key off.
 

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Discussion Starter · #3 ·
Answer

I don't want the fan running when the car is off- thus a switched source. This is not just my preference- from my understanding, this is the way it is done by others and by the manufacturer's installation sheet. I'm not sure what you mean by "I'm not sure why you're not installing the fan as its OEM" What is OEM? The fan? The fan itself is NOT OEM. To clarify, we are not talking about the AUX pull fan on the front of the radiator for the AC, this is a push fan on the back- engine side of the radiator. It was added on after a fan delete by the PO. I am trying to clean up his mess of wiring and wire this correctly. He added aftermarket Gauges and the Electric fan with a non-adjustable and poorly rigged controller- the way it was wired was a fire hazard, and it looked terrible. 16g spliced to 12g butt connected to 18g with a 7.5 amp blade fuse to a 30 amp blade fuse on the same bus. All wires of different gauge and no consistent color...No rhyme or reason to anything he installed. I am looking for the info to do this the right way from someone who has done it. I have done this type of thing on another car but the E36 is still new to me and I trying to learn. I can tap anything I want for the interior but the fuse box tapping is what I need the info on. I don't want to go overkill with this. Conversely, I don't want to skip corners and have a shoddy job that isn't safe. Let me know if you have any info to contribute that might help. Thanks. One last question- any recommendations for a 30 amp relay that I can add in line with the controller to tame the start spike? Again, I am here to learn and I appreciate any help you can give. I put this in every post- I have a lot of BMW specific electronic manuals and schematics that I will send to anyone who is willing to take a few minutes to help me out. Thanks again.

Alex J. Wechsler
 

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Okay, what I meant by OEM is the fan's original installation spec. If possible, I'd install it to that spec with only the switched source as any change. Normally, electric fans are wired to run with the key off in the case of unusual heat build up. But that should be a rare issue in a normally aspirated car.
 

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Just my 2 cents worth - I would be powering the fan relay directly from the battery. If you want the thing off when the ignition is turned off as a failsafe, run the switch terminal of the relay to a switched (ignition on) power source. Avoid connecting via the fuse box for the following reasons: 1. Additional heat generated inside the fuse box and feed in wiring loom due to the additional current load. 2. Reliability (the more connections, the more potential failure points) 3. If a failure in the fan circuit occurs, you wil avoid other circuits in the fuse box becoming collateral damage and a potentially complicated and expensive repair; and 4. Simplified troubleshooting in the event of a problem.

Since it is a thermo fan, unless you develop a problem with the sender or thermostat, it should only be running when the engine temperature is high (which eliminates running whilst parked unless you have cooked your engine), but also being cautious, I understand connecting to a switched power source just in case.
 

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Discussion Starter · #6 ·
Thanks

Thanks for the reply. I probably should have been an engineer for Mercedes as I tend to overanalyze and over-engineer things. What I am trying to do is ETREMELY simple. I got confused looking at the install instructions that came with the controller. My solution is very simple and will take about 1 hr to complete. I do need to find info on the optimal coolant temps for the M50 so I calibrate the thermostat. Any idea there. I have not checked on the board for that answer. Any ideas? OR...does this even matter? I am trying to get things tuned optimally. Thanks for the response. If there is any type of software or schematics you need let me know and I will get them to you.

Thanks.
 

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Thanks Alex,

I will keep you in mind. I would have a look at your thermostat opening temp and set the thermo fan to cut in just above that. From memory my E36 has an 88 deg thermostat and the standard is 92deg, so I would run mine at 90.
 

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Sorry, should have qualified my answer, all our temps in Oz are Celcius. 88 C is about 206 F (at the water pump) so it will be slightly cooler at the sensor on the radiator.
 

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Discussion Starter · #10 · (Edited)
Update:
For future reference:

1.) The power seat location in the fusebox is NOT switched, it is 12V constant- Stupid Idea to try to add to the fusebox for this application. Too many easily tapped 12v switched lines available to tap.
2.) Relay would serve no purpose for this application- another example of over engineering on my part.
3.) 12v switched wires are extremely easy to find if you have the center console and glovebox out. This site is a goldmine for anyone who needs a quick primer or a reminder that finding 12v switched power sources is not rocket science:
www.TechGuys.ca | How to: Find 12 volt source in a car
4.) If you have the spare cash, go for the SPAL with programmable controller. Easier install and better product- I have little to NO faith in the quality of the parts in the Hayden kit. This stuff was on the car when I bought it and came from Advance Automotive. Nice guys at Advance auto, I just don't buy parts from them. I will be replacing the fan and controller in the spring with a SPAL kit when I do the supercharger and engine internals project (spring=more money).
*This is the only BMW forum where anyone actually took the time to try to help out another member. I own a Volvo and use Brickboard.com all of the time for myself and to help others. If you have have any problems, post the problem and generally within half an hour you will get help from a Volvo tech or at least someone who knows what they are doing. It seems like other BMW forums I tried are more concerned with things that don't matter rather than helping other owner's DIY efforts. Thanks to everyone who took the time to respond. The offer still stands to everyone who took the time to try to help me out- if you need schematics or software let me know and they're yours.
 
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