E Box Fan

[jehu]

My ECU keeps overheating I haven't looked online yet I'm coming straight to the bimmer forums are these things available in in new stock I'll be checking that later but I figured I'd raise a discussion

[shogun]

Can tell you from my E32 750, temperature switch for e-box cooling E32 750: switch on at 44 +/- 3 degree C, switch off at 36 +/- 3 degree C. blower motor 12901720343
still available for the E34 http://bmwfans.info/parts-catalog/E3...trol_unit_box/
check the temp sensor inside the e-box

[jehu]

Can tell you from my E32 750, temperature switch for e-box cooling E32 750: switch on at 44 +/- 3 degree C, switch off at 36 +/- 3 degree C. blower motor 12901720343
still available for the E34 http://bmwfans.info/parts-catalog/E3...trol_unit_box/
check the temp sensor inside the e-box

Thanks I'll check that and make sure everything else is conducting air flow correctly without any impediments or disconnections I was assuming the fan was no longer rotating but I haven't had a chance to look at it yet just the the car started hesitating and when I opened it up the ICU woods extremely hot so apparently that's affecting its function they are OK once they cool down

[jehu]

So I jumpered the connector to the temperature sensor in the E Box and the fan spun so I'm assuming that indicates the sensor needs to be replaced thanks for all everybody's help

[jehu]

I wanted to expand on this issue if I may.

the engine has intermittently been hesitating, bogging and running badly to the point it almost wont move. I throw a 1222 fault when this happens.. If I swap in another DME it can clear up and start running fine (not always immediately strangely it can sometimes take a few moments)

This was why I considered the E-Box fan wasn't operating correctly because usually when I remove the DME to replace it with another it is extremely hot. Since this odd behaviour can occur with both of the units I have I am tempted to rule out problems in the circuitry of the units actually being weakened and rather just some general sensitivity computer circuitry has to high heat and they begin to fault.

I grabbed a third DME which works so far so good but haven't driven it long to get it hot. I ordered a temp switch but its going to be more than a week.

Has anyone had this problem occur before where you found your problem solved by fixing the not operational E Box Fan?

If you keep the AC Recirculate ON is that interfering with the E-Box air venting? I tend to use that frequently when in traffic to limit car and truck exhaust being rammed into my lungs and I wondered if this might in some way block the venting from the E-box.

[ross1]

Re-circ doesn't effect e-box cooling, it is independent of your HVAC.
I've never bothered to check the temp of a DME but the fact that it has a cooling fan indicates it needs to shed some heat. Have you done the proper diagnosis? Fan not coming on @ X temp, fan is good?
Either jump the temp switch wires or ground the brn one to test the switch. 12v at the grn/vio wire(engine running) at the fan? That wire is served by the fuel pump relay pin 87(1994 & 1995) so check for 12v there also.

[jehu]

So for some reason the mobile version I'm using pre selects delete post when I try and edit what I wanna say in addition is I thought I read show gun saying that the vent from the top of the E Box goes into the air Box and I wondered if the changing of the. vent veins might Stop

- - - Updated - - -

Yes I jumper the connector for the switch and the fan does spin I have another as I've said on order and I took one from my other car I'm gonna try and install that see if it helps I don't have any way of knowing if it works or not I suppose there's a an ohm resistance measurement I should be able to get I'll have to look into that I don't have time for that kind of thing at the moment though

[The Chauffeur]

Dumb question: Can this fan be *easily* retrofitted to cars without it? At least my '91 525 doesn't have it, I assume it wouldn't hurt... Would it be like a plug and play upgrade, kinda like the auto-dimming mirror, rear reading lights, etc?

[jehu]

The fan goes through a hole in the foot well fire wall behind the glove Box so you have to cut a hole if it's not already there and then you need this aicha a caller the fan itself fits into the hold it in place and create a seal into the bottom of the E Box so you'd have to use A&E Box from a car that had the fan and then replace all the guts

[shogun]

Not only these parts http://bmwfans.info/parts-catalog/E3...trol_unit_box/
you would also need the plastic duct from aircon housing top right to the housing of the fan motor behind/below the glovebox, probably item 3 http://bmwfans.info/parts-catalog/E3...ozzles_covers/

[The Chauffeur]

Great info, thanks! If the car was already pre-wired for it, I'd assume the cables would be tucked behind the glovebox or the passenger side speaker, good to know next time I tinker around that area...

[shogun]

The fan motor is pretty expensive, abt. 10 years ago I was searching for a new one because my one made noise, and I made some measurements: Maker Buehler, Nuernberg, West Germany, Buehler, Raleigh, N.C., USA, BMW Nr. 1720343.9 1.69.015.015-4 12V DC 43 S Made in W-Germany. Diameter 30 mm, Length 50 mm, from basis below to housing of the motor to end of the shaft at front where the black plastic impeller is attached. Diameter of plastic impeller/fan55 mm . Number of wings : 9
shaft diameter where fan is installed on: 2 mm (difficult to measure, approx.).Connection is inside e-box, but it cones out from behind the glovebox, so you have to open E-box also.

[jehu]

the wires for the fan would be in the E-Box If you want I'll take a photo tomorrow of the connectors for them.... there is also the temp sensor switch in the E-Box to consider...

[The Chauffeur]

the wires for the fan would be in the E-Box If you want I'll take a photo tomorrow of the connectors for them.... there is also the temp sensor switch in the E-Box to consider...

That'd be awesome, thanks!

I've noticed many of the required parts are interchangeable, like the rubber grommet for the actual duct (it's a closed rubber flap on cars without the fan, easily replaceable), but you're right, I haven't noticed if there's a threaded hole for the switch, I'd assume it goes on the metal portion of the frame?

I never quite understood why BMW didn't add the fan to the whole lineup, is it just for the bigger engines? But you'd think even an M40 makes enough damaging heat during the years, especially in hot climates...

[davetrfl]

Could a fault in the E Box Fan affect the voltage going to Fuse 23 for the fuel pump? Jumping 30 to 87 at the relay connector does not turn fan on or provide power to fuse 23. Any ideas folks. Thanks!!