I have a UK n/a xf, I have just found a broken negative wire on that unit. It is bolted with 2 bolts under the drivers side headlight, it has 2 wires going to it and one pipe coming from the 2 small canisters and one pipe going to the engine. Can this be fixed as the pole has corroded or is it a new unit? What is the unit called?

 

That is the "REST" pump. It circulates hot coolant fluid through the heater core when you press the "REST" button on the A/C control panel and leave the car with the engine off to keep the inside warm. It is your choice as to whether to fix it, or just leave it.

 

Thanks for that, can the connection be fixed or is it replace the complete unit?

 

Without actually seeing the unit ( or a good picture of it ), I couldn't say

 

Does the electrical connection come off the unit as this is at fault not the main unit? One of the poles is corroded and the wire has snapped away from it.

 

If the electrical posts on the pump are too corroded to accept a connection, then I'd say you need a new pump.

 

Does this electrical connection come away from the pump?

 

The pump has an extension on the motor end cap with 2 round brass pins that the harness connects to. If the pins are gone, then you will need a replacement pump.

0 392 020 029

http://www.ebay.co.uk/itm/Engine-Aux...-/400811647700

 

And there we have another clear and complete diagnosis from our very own Dr. George (ala_xfire)!

 

Is it possible that the cap can come off, have wires attached to the contacts inside, then have the wire protrude from the cap which is resealed by silicone and have the ends of the new wires attached to the existing plug on the harness?
Maybe the plug has to be cut off and have an insulated wire to wire connection
I'd sure hate to toss out a perfectly good pump if it is still working.
It may not look too pretty but whose looking anyway?

 

Thanks for the reply's, the poles seem ok just one has some corrosion on it and the wire has come away. Does the plastic cap which has a cover over the poles actually come off? Also how are the wires connected?

 

The plastic cap COULD come off, but is not designed to.
It is held in place by bent metal fingers which are part of the metal surround.
The pins are connected internally to the motor brushes.

Externally, there is a 2 pin plug from the harness to the motor. The plug is keyed to prevent swapping the + and the - polarity.

( I know all this, because I have one sitting right here on my desk that I saw on eBay for $10 )

 

Yes I see the + & - symbols, so does this separate from another plastic part? Sorry for being so thick, I just don't want to break anything.

 

I don't have access to the harness connector, but here is a picture of the 2 pin connection on the pump :

 

Thanks for all he help ala-xfire, I got the harness plug off and the poles on the pump are fine. The problem is the harness plug, the wire has snapped at the solder, so I have ditched the harness plug and just used 2 female red bullet connectors which fit nice and snug.

 

Just curious, have you tested it? The R.E.S.T. feature is really interesting, but I doubt many people ever use it. Also, did you take any pictures?

 

Hi, no i have not tested it yet as battery is disconnected as car is in the middle of strip down. I don't like to see broken wires so that is why I sorted it out. I will see if it works when all sorted. What pictures were you after?

 

The damage to the wires/connector, was it just caused by age/weathering, or did something tear it apart.

 

I think it was more likely to be an age thing as pole connector in the harness plug was corroded and the wire seems to be quite hard.

 

Found this thread whilst researching heater issues. I was perusing the Xfire shop manual and it states:

"The coolant circulation pump (5) serves for maintaining a uniform flow of heating water through the heater core (4) even at low engine speeds and in the residual engine heat utilization mode (REST)"

I've been testing mine because I don't think it's pumping well (my heater is not getting very warm) and on my car it's running whenever the engine is running and the heater is on (which confirms the description above).