Hello Everyone,

Looking at the wiring diagram the auxiliary coolant pump power being is fed from the F8 10A fuse which is being fed by the R1 Blower Relay (5 pin). The blower relay looks like gets a output ground control from the Climate Control Module. (if I'm reading the wiring diagram correctly). I'm curious when causes the climate control module to activate the blower relay to power the auxiliary coolant pump? The blower motor and auxiliary pump both receive power from the R1 Blower relay.

I'm getting heat at idle with the car sitting, so I think I'm fine, but I tried feeling for coolant flow from the aux coolant pump. hard to tell for me. I'm just curious if there is an way to test for proper pump operation with the aux pump in the car?

thanks so much!

 

Hi mpasiuk,

The Electrical section of the Workshop Manual explains the Climate Control System operation, but unfortunately the description of the Auxiliary Coolant Flow Pump operation is brief:



Due to its placement, it's not easy to put your hand on the pump - it may be easier from below. You can raise and support the car, and while the engine is idling, feel the pump motor for vibration indicating that it is running.

With a mechanic's stethoscope, you can feed the probe down alongside the coolant reservoir to make contact with the pump and listen to the pump. If you don't hear the electric motor running with the HVAC system on, the pump is dead.

You can download the Electrical / Climate Control section of the Workshop Manual from this forum at the link below:

Jaguar X350 Workshop Manual - Electrical / Climate Control Section

Cheers,

Don

 

Thanks Don, I have rep[lace the coolant tank, so I will be doing the aux pump as well. Two birds w/ one stone. I've read the electrical manual, but I was like to understand the logical that the Climate Control Module uses to activate the aux pump.

thanks again

 

The aux pump is always on when the HVAC system is on. Other members have pulled the fuse (in the trunk) to disable the pump in summer when it's not needed.

 

Thank You!

 

youve got my brain thinking.

so if folks are shutting it off in the summer, im assuming its only purpose is to help send hot coolant to the heater core?

does this help the AC cool better? I seem to have a problem where I have to set the temp at 64f to feel comfortable. In my other car and in the house I usually have it set to 69 or 70 to be cool in the hot summer. If its set at 67 or higher its way too warm. I wonder if my pump is affecting it. But the temp should be set based on the feedback from the interior temp sensors. I better make a separate post

 

I had to replace my pump recently. Simply did not get much heat in cabin. pump was $120 delivered. Not simple to install. my 2004 had 105K miles on it for reference.

RyeJag

 

Im very curious..how much did the heat improve after your install? Thanks! I’m thinking of replacing mine when I do the coolant overflow tank in the spring .

 

And to ryejag -
How did you install it? Did you replace any other nearby hoses or cooling parts at the same time? Thanks.

 

Best way is to measure the heater hose before turning the HVAC on then have someone turn the HVAC on high heat while you keep the infrared laser on the hose to the heater core, you should see an immediate increase in temp at the hose.

 

it's tucked away low down on the inside of the engine bay between the radiator and the engine, I checked mine with a power probe, which allows you to power up parts individually, and it was dead, bought a new Jag part and tested it in the same way off the car, the hoses in that area "seemed" ok, so I didn't change any, but since then, and it's only been maybe 6 months, I have had two supercharger coolant hoses go top front.