Radiator outlet temp sensor wiring missing from harness and DME

Rplain · 03-16-2016, 07:08 AM

Kind of new here... and I've been in the vw/ audi game for a long time... but finally made the switch over to the darkside!

So long story short guys... I traded my old Z for an 08 328i auto with 34k miles that I knew would need work. it was hit in the font end but fixed... assuming it was rewired... and that the DME was replaced (newer date stamped on it)... I cut apart the harness and couldn't find the wiring for the coolant temp sensor for the low rad house (outlet). I pulled apart the dme box and it wasn't pinned in AT ALL. (pins 6 and 19 I believe)

So I have 2 questions...

1. How many different cooling systems do they make and did one exist without that rad outlet temp sensor? or do they all have them?

2. If its completely missing from the DME harness and it NEEDS to be there... Could I damage/fry the DME by pinning the two wirings in there? since it should just be resistance and a signal... it shouldn't damage anything correct? especially since it should be in there in the first place.

Any other info you guys could share would be awesome too!

THANKS!

hassmaschine · 03-16-2016, 08:04 AM

the radiator temperature is primarily used to control the radiator fan. without it it probably uses some sort of limp map, but that isn't ideal.

I would wire up the connector back in and reinstall the sensor. Why people hack stuff out of a car like that I'll never understand.

Rplain · 03-16-2016, 08:51 AM

yeah well it was faulting for the fan not working at all... rewired the fan (its a direct wire splice not a plug and play)... so it was throwing a fault and DEF was in limp mode lol. the faults off and MOTIS can test the fan now so it works.... but it just blew my mind that the sensor wasn't even in the harness/ pinned to the DME. that's my issue lol it won't kick the fan on. I was just worried since it wasn't in there it could damage the DME. that was my main concern.

but I agree with you. whoever did this prior to me is an idiot.

hassmaschine · 03-16-2016, 09:56 AM

It won't hurt the DME if it's missing, but it will hurt your engine if the fan doesn't come on.

Rplain · 03-16-2016, 10:07 AM

lolololol

I meant I was worried it could fry the DME if I wired them in. but you sure? I heard running it super hot temp is what all the track kids are doing these days.

hassmaschine · 03-16-2016, 12:56 PM

no it wouldn't hurt it. I doubt even if you shorted the two pins together that it would do anything.

I picked up a DME a few years back that had been in a fire/accident. The motherboard was bent like a taco, but it still works fine.. they're pretty tough, and there's all sorts of circuit protection built in.

Rplain · 03-18-2016, 11:51 AM

thanks man. I really appreciate it!

Rplain · 03-18-2016, 01:45 PM

So heres the new deal... wired in the coolant outlet temp sensor to the proper pins. (6&19)... now the fan will come on at 160... and shut off at about 180 and not come back on again at all. When I unplug the upper coolant temp sensor on the block... the fan comes on full force and you can hear the water pump kick on to circulate. any idea as to why the fan won't come on like it normally should?

03-16-2016, 07:08 AM	#1
Rplain New Member 0 Rep 9 Posts Drives: 08 328i montego blue Join Date: Mar 2016 Location: Poughkeepsie iTrader: (0)	Radiator outlet temp sensor wiring missing from harness and DME Kind of new here... and I've been in the vw/ audi game for a long time... but finally made the switch over to the darkside! So long story short guys... I traded my old Z for an 08 328i auto with 34k miles that I knew would need work. it was hit in the font end but fixed... assuming it was rewired... and that the DME was replaced (newer date stamped on it)... I cut apart the harness and couldn't find the wiring for the coolant temp sensor for the low rad house (outlet). I pulled apart the dme box and it wasn't pinned in AT ALL. (pins 6 and 19 I believe) So I have 2 questions... 1. How many different cooling systems do they make and did one exist without that rad outlet temp sensor? or do they all have them? 2. If its completely missing from the DME harness and it NEEDS to be there... Could I damage/fry the DME by pinning the two wirings in there? since it should just be resistance and a signal... it shouldn't damage anything correct? especially since it should be in there in the first place. Any other info you guys could share would be awesome too! THANKS!
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03-16-2016, 08:04 AM	#2
hassmaschine Major General 3973 Rep 7,215 Posts Drives: "NBO" 330i Join Date: Jun 2014 Location: earth iTrader: (0)	the radiator temperature is primarily used to control the radiator fan. without it it probably uses some sort of limp map, but that isn't ideal. I would wire up the connector back in and reinstall the sensor. Why people hack stuff out of a car like that I'll never understand.
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03-16-2016, 08:51 AM	#3
Rplain New Member 0 Rep 9 Posts Drives: 08 328i montego blue Join Date: Mar 2016 Location: Poughkeepsie iTrader: (0)	yeah well it was faulting for the fan not working at all... rewired the fan (its a direct wire splice not a plug and play)... so it was throwing a fault and DEF was in limp mode lol. the faults off and MOTIS can test the fan now so it works.... but it just blew my mind that the sensor wasn't even in the harness/ pinned to the DME. that's my issue lol it won't kick the fan on. I was just worried since it wasn't in there it could damage the DME. that was my main concern. but I agree with you. whoever did this prior to me is an idiot.
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03-16-2016, 09:56 AM	#4
hassmaschine Major General 3973 Rep 7,215 Posts Drives: "NBO" 330i Join Date: Jun 2014 Location: earth iTrader: (0)	It won't hurt the DME if it's missing, but it will hurt your engine if the fan doesn't come on.
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03-16-2016, 10:07 AM	#5
Rplain New Member 0 Rep 9 Posts Drives: 08 328i montego blue Join Date: Mar 2016 Location: Poughkeepsie iTrader: (0)	lolololol I meant I was worried it could fry the DME if I wired them in. but you sure? I heard running it super hot temp is what all the track kids are doing these days.
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03-16-2016, 12:56 PM	#6
hassmaschine Major General 3973 Rep 7,215 Posts Drives: "NBO" 330i Join Date: Jun 2014 Location: earth iTrader: (0)	no it wouldn't hurt it. I doubt even if you shorted the two pins together that it would do anything. I picked up a DME a few years back that had been in a fire/accident. The motherboard was bent like a taco, but it still works fine.. they're pretty tough, and there's all sorts of circuit protection built in.
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03-18-2016, 11:51 AM	#7
Rplain New Member 0 Rep 9 Posts Drives: 08 328i montego blue Join Date: Mar 2016 Location: Poughkeepsie iTrader: (0)	thanks man. I really appreciate it!
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03-18-2016, 01:45 PM	#8
Rplain New Member 0 Rep 9 Posts Drives: 08 328i montego blue Join Date: Mar 2016 Location: Poughkeepsie iTrader: (0)	So heres the new deal... wired in the coolant outlet temp sensor to the proper pins. (6&19)... now the fan will come on at 160... and shut off at about 180 and not come back on again at all. When I unplug the upper coolant temp sensor on the block... the fan comes on full force and you can hear the water pump kick on to circulate. any idea as to why the fan won't come on like it normally should?
	Appreciate 0 Quote