Hi Guys,


Just curious how you can check to make sure if the electric fan works or not. Take it on a long drive and then park it and turn off? Should it run when the car is off? My 90 XJS has always stayed below the N on the gauge but I never really noticed if the fan runs or not. Where I live its mostly rural driving and not stop and go.


I actually was just sitting here this morning and this question popped into my head. LOL. I'm in Wisconsin so the crappy weather really wont let me drive it for a few days to check it out. Thanks...

 

It changed with various models, but in principle yours will be one of:

• Comes on 100% of the time with the aircon, will run on post shutdown if water temp sensor warm enough
• Comes on with aircon if certain conditions met (do not know what they are), will run on post shutdown if temp sensor warm enough

Mine comes on 100% with the aircon on.


Greg

 

Yeah, it gets a little weird 1989-later. I was just looking at a 1989 schematic and there is no tie-in with the climate control at all after vin 156989. It's purely coolant-temp triggered. But the post-shutdown cooling capability remains.

Probably best to find an actual 1990 diagram.

In some cases the climate control wiring and functions are different between coupes and convertibles....which *might* include differences in the elect fan circuit as well..

Cheers
DD

 

You guys know I'm not into electric/schematics. LOL... At least with your help, I fixed my power window issue. I was lucky it was just the breaker.


I really have not paid any attention to the electric fan because the temps have always been slightly below the N on the gauge. My vin is 174 something and I was curious if it always ran or not. I do know it does not run when I have the car idling in the driveway. I probably should give the car a good run and see if it does kick on. Thanks.

 

If you want to test the fan, jump the connections each side of the temp thermostat on the water pump and it should come on if the igntion is on. DO NOT try this with the engine running though!

Greg.

 

So, I should disconnect both connections from the water pump and touch them together with the ignition key in the 1 or 2 position? Or run a wire between the two, while they are still connected to the water pump? The electric fan should then run? I wish you guys lived near bye. LOL... Thanks for your help.

 

Pull the insulated connectors from the thermo switch on the water pump inlet and touch them together or run a short wire (or iron nail) between the two metal connectors inside the insulation, ignition on, engine NOT running.

Greg

 

Thank you.

 

I pulled the two connectors, attached them to a 30 amp fuse, then turned the ignition to 1-2 position and the fan came on... That made my day guys. LOL. The connectors and thermo switch looked pretty dirty, so I cleaned them up and reconnected them. They were very loose, so I also tightened them up a little for a better connection. The next time I am on a long run, I will check the fan while idling and after turn off and will see if the fan runs... If the fan does not run, maybe its the thermo switch. Do those go bad? Thanks for your help guys.

 

They do go bad, not often, and the wrong one can be installed too. Not a bad idea to buy a new one (I think they go on and off at 85°C). The coolant runs out when you unscrew the switch so you can change the stuff at the same time!

Greg

 

as this is the over run thermostat , you can put the connections together even without the ignition switch on , or even in,

as when you turn off and leave the car , the fan continues to run using this stat ,

i used this same thermostat/switch to run my full electric setup ,

and it works very well ,


BB

 

How did you use the thermo switch to run your full electric setup? Thanks.

 

I did drive the car today for around 45 minutes and the gauge stayed right at the very bottom of the N on the gauge. Man, this car drives like its brand new, I love it. LOL.


The electric fan did not turn on when I parked and turned off the XJS... Since its only 55 degrees here in Wi, maybe the electric fan just will not turn on because its just not running hot enough. If it was summer, maybe it would... It is a 1990 XJS, so maybe the fan does not run unless it gets above a certain temp. Thanks.

 

i used the thermo switch to operate a relay to run the new electric fans, while retaining the small electric fan as well ,

so at 85 degs the fans kick in

BB

 

Which switch did you buy and where did you purchase it? Thanks.

 

I am actually thinking of finding a M22 X 1.5 two position switch that comes on around 10 degrees earlier then the original one does. From what I have read, it sounds like around 96C it switches on then goes off around 91C. I thinking a 85C switch might be better... Some recommend the 82/77 switch but the fan may run too often.

 

HI guy i have same problem and after reading manuals and sights i linked to wires on the thermostatic switch and my blowers blew and fan did not work but fan workes with direct wire. Is there a fuse for the fan blowers under the scuttle

 

I HAD THE AIR CON ON BUT ENGINE OFF WHEN TRIED SILLY FOOL. would anyone have any photos of where i shoul be looking and what to connect to the car heats up in traffic above the N and the aux fan does not come on.

 

Luds

if linking the wires on the thermostatic switch, ignition on, does not make your aux fan work, but hot-wiring it does, then as you say the problem is getting current to the wire to the switch. The fuse is the one nearest to the front of the car on the US driver's side inner wing fuse box, by the bracing strut. The fuse may be burnt out or just a bad one, and there may be bad connections on the fuse holder itself. There should be current at the fuse, igniton on.

The relay for the aux fan is under the plastic cover on the engine side rear of the US driver's side headlight nacelle. There are three there: top = headlights, middle = horn, bottom = aux fan.

If these all check out and there is current to the aux fan from the relay and still the fan does not come on, the thermo switch is suspect.

Greg

 

Hi Greg thank you for the quick responce i will check this when i get home. also the thermo switch is the one near water pump in middle with two spades on