[Bamaben]

This is the thermostat connector. If wires touched would it throw a thermostat code or would it short the thermostat out or would it do nothing?
I ask because I got a tstat P0128 low coolant temp code. Is this responsible for that code or does the coolant temp code get thrown by another sensor?
I cleared code. few days later it threw it again. I replaced tstat and in doing so noticed this. So now I'm wondering if this shorted my old tstat or caused the code. I do believe tstat wasn't working when I replaced it because oil temp wasn't getting above 210. I'm wrapping tape around wires to prevent them from touching. I'm hoping that the tstat was just bad and wires didn't cause codes or tstat to go bad. Anyone with electrical knowledge know?
Thanks

[3SPKY5U]

If the wires touched it would probably blow the fuse and cut the controller off from the thermostat.

[Bamaben]

Originally Posted by 3SPKY5U

If the wires touched it would probably blow the fuse and cut the controller off from the thermostat.

I thought about possibility of throwing a fuse but I don't have any blown fuses. Does not having a blown fuse mean the tstat was really bad and wires never touched?
I'm trying to make myself feel better about replacing the tstat because the tstat was bad and not simply the wires were bad.

[3SPKY5U]

Originally Posted by Bamaben

I thought about possibility of throwing a fuse but I don't have any blown fuses. Does not having a blown fuse mean the tstat was really bad and wires never touched?
I'm trying to make myself feel better about replacing the tstat because the tstat was bad and not simply the wires were bad.

It's possible. I know when my tstat started to fail it would throw a code... I would clear it, it would be fine a week and then throw another code... it only has to be off like a millimeter to throw a code.

[Blackhawk36]

If the touch (or if one is broken) the thermostat will failsafe and stay wide open. The car will not get to operating temp within the prescribed time and you get P0128.

[Bamaben]

Originally Posted by Blackhawk36

If the touch (or if one is broken) the thermostat will failsafe and stay wide open. The car will not get to operating temp within the prescribed time and you get P0128.

So you're saying wires touching would throw that code? How did you know this?

[Efthreeoh]

Originally Posted by Bamaben

So you're saying wires touching would throw that code? How did you know this?

There is a heating element in the t-stat. The wires power the heating element. I would suspect that if the wires shorted, the diagnostic circuitry would detect an abnormal current load and determine the heater element has failed.

[Blackhawk36]

Originally Posted by Bamaben

So you're saying wires touching would throw that code? How did you know this?

Not because the wires touch. If they do touch the thermostat doesn't close and the engine doesn't warm up quickly enough and the DME sets the code.

[Bamaben]

Originally Posted by Blackhawk36

Not because the wires touch. If they do touch the thermostat doesn't close and the engine doesn't warm up quickly enough and the DME sets the code.

So you're saying it would either fry the tstat . I believe mine was stuck open constantly. I found a thread where others have the same naked wires showing there. I'm betting this very common since all our cars probably have that terrible angle the wires have to the tstat. It's like they're folded at a 60 degree angle. No telling how many.

[Blackhawk36]

It shouldnt hurt the thermostat at all. It just won't work. The thermostat is designed to fail in the open position so you don't smoke your engine. You just need to fix your your wires before you decide you have a bad thermostat. It is probably fine.

[PichaDis11]

I wouldn't use tape because the heat from the engine would render the adhesive side of the tape useless over a period of time. I suggest using some heat shrink wraps.

[Blackhawk36]

From the manual:

If the engine overheats or runs too cool and no other cooling systems indicate trouble, the thermostat may be faulty.

The electrically heated thermostat is monitored by the OBD II diagnostic software. The fault may lie in the DME software or hardware, or it may lie in the wiring to the thermostat.

You have confirmed you have a problem in the wiring to the thermostat. That is what needs fixed.

The yellow wire carries voltage from the junction box to the thermostat and the white wire provides a ground through the DME.

[Bamaben]

Originally Posted by Blackhawk36

It shouldnt hurt the thermostat at all. It just won't work. The thermostat is designed to fail in the open position so you don't smoke your engine. You just need to fix your your wires before you decide you have a bad thermostat. It is probably fine.

Too late. I replaced tstat yesterday which is when I found the wires. So it is a 50/50 chance the tstat was fine and just wires touched. Last time code was thrown I was sitting still and had been driving a while so maybe pump was really just stuck open too long indicating bad pump. Today with new pump temp went higher so I know wires aren't completely shot. I'm just paranoid to drive it again until I wrap those wires.
Is there a way to test old pump now that it is out of car?
Not that it matters other than to make me feel better

[Blackhawk36]

You can apply 12 volts to one side of thermostat and ground the other pin. If it closes you know it was good. The circuit is protected by a 30 amp fuse behind the glove box. If your production date 03/07 through 08/07 it is fuse #78. 09/07 and later is fuse #37. You should fix the wire, not just that them. Some of the strands of wire are broken. If a lot of current (30A) goes through the wire it could overheat and burn through.

[idrift4wd]

why dont you use electrical tape? and tape both off.

[Bamaben]

Originally Posted by idrift4wd

why dont you use electrical tape? and tape both off.

I'm going to.

[Bamaben]

Originally Posted by Blackhawk36

You can apply 12 volts to one side of thermostat and ground the other pin. If it closes you know it was good. The circuit is protected by a 30 amp fuse behind the glove box. If your production date 03/07 through 08/07 it is fuse #78. 09/07 and later is fuse #37. You should fix the wire, not just that them. Some of the strands of wire are broken. If a lot of current (30A) goes through the wire it could overheat and burn through.

My production date is 02/07. I don't have a way to put 12 volts to it.

[Blackhawk36]

Originally Posted by Bamaben

My production date is 02/07. I don't have a way to put 12 volts to it.

Ok. Then you can't test it.

[E90Ryan]

Wrap with electrical tape, plug in, move on..

[TeinBMW]

Kaboom!

You should never have exposed wires like that. That's asking for trouble man. Wrap each wire up with electrical tape and get them replaced.

[Bamaben]

Wrapped wires but one broke off when putting it back in tstat. Anyone know where I can buy a new connector or how to get wires out of this one?
Thanks

[Efthreeoh]

Originally Posted by Bamaben

Wrapped wires but one broke off when putting it back in tstat. Anyone know where I can buy a new connector or how to get wires out of this one?
Thanks

You can find all the parts on realOEM.com. BMW sells the connector, new pins and the little seals.