I just had a quick question. Does the auxiliary Water Pump runs all the time?

I had it out while changing my water pump and it doesn't go on when I turn the key or the car on. Then I unplugged it, and tried it with a tester-light and I didn’t have any current. So I traced the wire (red with a white line), back to the fuse box and the wire goes to a mini relay were it runs off from one of the two biggest tabs. The other biggest one has full time current... By placing a bridge with a "U" shape wire and connect the two places where the big tabs go in, and turned the ignition on and this forces the pump to run.

All I know is that relays work as electrical switches that allow small current to flow to a higher current... So my best guess is that the pump doesn’t run all the time, and if it does, I've got a real problem 'cause is not...

Also want to mention that my DCCV is not working, and for the diagrams I've seen this pump does helps circulate the coolant through the AC heater system. Maybe having a bad DCCV may cause it to not work properly? I too have tried to make the car run with the heater system on and nothing made the pump run...

Besides the two biggest tabs on the relay, there also are 3 smaller tabs. On one of the small ones, it has a brown with a little green line wire; the other one is empty and the third one has a yellow wire that goes from this one back to the "all the time" running current bigger tab...

 

I bet JagV8 will give ya an answer...soon.

 

Great info (recommended)!
http://www.autoshop101.com/forms/hweb2.pdf

The relay is a 5 pin, but because the one (small pin) is bridged with the bigger one (the one with always current), then it is made to work as a 4 pin. I guess Jag did this 'cause it makes things easier, by having a car that uses mostly 5pin relays, the owners can easily swap and use a 5 pin in a 4 pin system; without worrying about having to have both types (5 and 4 pins)...

Well, so if it works as a 4 pin, then, it maybe hints to me that the pump shouldn’t have to work all the time. The relay is an “on” and “off” switch. Only when the relay is activated, which now “how” or “why” this happens is a mystery to me… Humnn. Anyone???

By the way, and as a side note, the SC's electric coolant pump does work as soon as I turn the ignition switch on... No relay for this one. (I think this is the answer)

 

Checked JTIS yet?

 

No, even though I have it, it wont run on my computer... Wind 7. :/

 

Yes for Win 7 the JTIS needs to be run on "Virtual Windows XP". This is a free download from Microsoft. I run Win7 Ultimate N 64 bit and it works fine.
.
.
.

 

No friends with a window xp or w7 32bit?

 

It may depend on which variant of the S-Type you have and as I don't see it in your post I don't have an answer.
Be VERY careful how you use a tester light on any modern car. You are quite likely to destroy modules etc unless you are REALLY sure you know what you're doing.
Ouch. Same comment.

BTW, the electrical diagrams are all PDFs. Many are on the web and people have posted links to them before.
I would not be doing what you're doing at all without first reading the diagrams (and I would not be using a tester light at all). I would be scared of a huge $$$ cost.

 

The car is an S type R 2003

JG

 

I know about the IC circulation pump which does run all the time on my 05 STR but what's an aux water pump?

Bob S.

 

Here is what the JTIS says about the AUX coolant pump.

"Auxiliary coolant flow pump vehicles fitted with 4.2L engine. The auxiliary coolant flow pump is electrically driven and provides increased coolant flow during low engine speed operation. The pump is also used to circulate coolant after the engine is turned off under certain conditions".

So I still don't know if it runs all the time? I don't think it does because the pump can run after engine shut down if needed. So this sounds like the computer is monitoring temperatures to decide if the AUX pump should be running. The only problem that has been reported when the AUX pump fails is lack of cabin heat at low engine speeds/idle. Never any mention of engine temperature problems?? Just to be clear ONLY the 4.2 L V-8's NA and SC have this pump. The 6 cylinder cars do not.
.
.
.

 

A BIG + for you, AWESOME JOB clubairth1!!! Thats it, it doesn't run all the time!!! This confirms my theory behind the relay working as a 4pin ("on" & "off" switch).

WOW I was even happier to read "The only problem that has been reported when the AUX pump fails is lack of cabin heat at low engine speeds/idle. Never any mention of engine temperature problems"

JG

 

Thanks for explaining that.

I wonder if it too is magnetic drive like the IC pump on the STR?

Bob S.

 

Yes it is!

JG