Yes, the wires can be indvidually tested with an ohm meter if you have one.

In your case jumping the switch effectively tests the rest of the system: if the fan runs, which yours does, you know that A) the wires are Ok (or the fan wouldn't run) B) the fuse is good (or the fan wouldn't run) C) the grounds are good (or the fan wouldn't run) and D) the relay is good (or the fan wouldn't run)

If you jumped the wires at the switch and the fan did NOT run then things get a bit more complicated.

Cheers
DD

 

Cassidy, fyi the cooling fan temp. switch is $27 at autohausaz.com.

 

bigwiki: Thanks for the link.

Doug: Thanks for explaining things in elementary terms that I can understand.

Everyone: I apologize for my spelling last night -- geesh it's bad. I attribute it to a long day.

As I insinuated in my first post, I assumed their was a tie in between the air conditioner and the aux fan. Since learning that is not the case (thank you Doug), I'm a little concerned that the aux might actually be working. When I get the coil/module problem fixed, I'd like to test to make sure the fan is not actually functioning properly. As I understand it, the fan should kick on after the thermostats reach a certain degree and when the engine is shut down under high temp conditions. After researching some other threads here and on other sites, I'm starting to think that a faulty fan clutch may be my problem -- as I understand the aux fan is not strong enough to cool the system (when running) if the clutch is bad. What do you guys think? How hard is it to replace the clutch?

 

The fan clutch is not hard to replace. Some dexterity is needed to deal with the four nuts, though, as working room is tight.

Go out and spin the fan with your hand. If it spins freely, the clutch is no good.

If it doesn't spin freely you'll have to wait until the car running again before testing it further.

Warm up the engine so the temp needle is creeping past the "N". Now stop the engine and spin the fan by hand. It shouldn't spin more than one turn. If it spins freely, the clutch is clearly faulty and needs to be replaced. If it doesn't free spin but does spin more than one turn, it's "iffy" and should be replaced.

Cheers
DD

 

Replacing the fan clutch is quite easy, four nuts hold the fan and clutch onto the hub. Getting around the fan shroud is a pain and you'll probably have to remove it, but that isn't too much of a hassle.
You might consider springing for a double electric fan and just remove the fan clutch and auxiliary fan.

 

Doug: I performed that check previously and in both cases (cold and warm/hot) I could never get the fan to even spin an entire rotation. So, maybe the clutch isn't the problem. All I know is that I want that temp needle to stay between C and N. Period. That begs the question: Assuming the aux fan is not working properly, will fixing it solve my problem? Other than the aux fan and the clutch, what other issues might be present?

Jamey: I would love to get the dual electric fan and forget about it, but unfortunately the price (approx $500 for the fan alone -- I don't think I can install it myself) is too much for the time being. It is definitely on my list of future upgrades though.

 

Anyone know where the fuel pump relay is?

 

It may well solve your problem....those little aux fans DO make a difference. If not I'd have the radiator cleaned.

I agree...the fan clutch sounds like it's OK

Cheers
DD

 

Hi Cass, I assume you have a late model Marelli like mine - my aux fan cuts in at around 95degC

On cold days it does not even come on sometimes. It does continue to run when engine temp is hot after shutdown.

I have just undergone a complete cooling system overhaul and I still have the temp gauge going up to the N with 82degC themostats. If I turn the car off and immediately re-start the temp has come down so I suspect either a bad Temp sensor or that is how my gauge is calibrated.

Dual Electric fans will not necessarily fix the problem - a mechanical fan will move far more air even at idle (if the clutch is ok) your mechanical fan is a 5hp job.

 

There seems to be a debate on electric vs mechanical fans, both have advantages. While Warrjon is correct in that the power that drives the mechanical fan is much higher than an electric, the CFM it produces at idle is questionable. CFM increases with engine speed, but it is widely agreed that beyond 30-35 mph the fan does nothing. I've looked and am unable to find any specs of what a stock mechanical fan pulls for CFM. The stock electric aux-fan is only 650 CFM.
Mechanical fans are reliable and cheap. There is very little that can go wrong. ie: broken belt, failed clutch.

Electrical fans are constant speed (although a few brands have variable speeds) and require installation of more wires, temp switches, fuses and some require a higher alternator output. They come in various CFM and prices can be in excess of $500, however some produce 5000 CFM which would be far above the mechanical specs at idle. When running they are louder too. They do not drain power off the engine when not running.

I think it's a personal choice.

 

I installed an electric fan in my Mercedes. Total parts (fan, relay, temp control module) cost was about $120. It works pretty well. But the Jaguar fan clutch is surprisingly cheap ($40 online). So, I think I just stick with fan clutch for the Jag.

 

Hi all,

Honestly, after seeing all the overheating issues on the forum, I had to get on and try to convince you to get some electric fans. Yes, they are a bit expensive, and I would personally steer clear of www.v12's.com after a bad experience, however...

I have 2 fans around 40cm each, one runs on the A/C and on a 90C temp switch in the water pump housing(?). The other runs independently on an 82C temp switch in the R/H hose feed to the radiator (yes, I know, restricting the flow, but only marginally). That second one will keep running, and cycle on and off after shut down. The fan(s) only come on for 15 to 30 seconds at a time, even in 35C+, and very rarely does the system actually run both fans together. There is nothing I can do to overheat my '84 XJS.

Yes, the OEM system will work if you want to nurture it every step of the way, but do you really need the hassle. Don't you have fuel hoses, spark plugs, harness, fuel filter and/or paint color to change?

Regards

Matt