Gah!

I just realized it's a '96, not a '99. <flail>

Okay, so figure this one out:

I'm looking at NAPA's site. The outlet/plug for my Temp Sensor looks like this:

http://partimages.genpt.com/largeimages/501974.jpg

which is only listed for the '99, not the '96. All of the ones for the '96 look like this:


http://partimages.genpt.com/largeimages/501978.jpg

I was hoping to look and see if I've purchased the wrong one, meaning the one I installed had different outputs and that could be the problem. Any thoughts?

And more questions: I noticed that the spec stated "Coolant Temp Sensor Temp Rating : 10,000 Ohms At 77 Deg. F". Does the resistance drop as the temperature goes up? If so, if everything else is working fine, wouldn't the sensor unplugged cause the brain to assume the engine is really hot so the fan would turn on? It seems if that is the case, then it would be a quick and easy way to check the sensor, and by default then, if the fan does not turn on then the problem is elsewhere.

I changed the relay before my first post. Are you saying to drop another $50 on another one?

Or was I not clear that I changed it?

I meant to say that after watching the YouTube vid on changing the fan, I realized that the problem could be the relay. I did the test that the guy suggested and realized it was bad so I replaced it..

I'm not trying to be short here, I'm just making sure I'm following you correctly.

Oh, it's the same part number for both the '96 and the '99 relay, thankfully.

Welp, kind of answered that one. After checking the plug before my last post, I forgot to plug the sensor back in. Just ran an errand with the van and before I was out of my driveway I noticed that the fans were going full-bore.

So, does that mean it's the sensor that's the whole problem?

I tried to turn on the AC a while ago to see if that would kick on the fan and it didn't. I'd go try again but my wife has the van right now...

If the AC doesn't kick it on (after the sensor is reattached), then it's not just the sensor.

grrr...

does your temp gauge inside on the cluster work correctly? does it show temp? if it does the temp sensor is and will not be the issue. and FYI the fan relay U got is under a warranty take it off go get another one say this one worked for a day then quit get a new one.

Yes, yes, and will do.

Done.

Plugged everything back in. Started the van. Turned on the AC.

Nothin'. Fan still isn't working.

PCM??!?

ok ok back to basics the fans were working b4 u replaced it now after u replaced it nothing I would plug back on old fan assembly and go from there something not right things dont just not work after u replace it unless something was done wrong or forgot something or wring part.

The fans (at least one) were working but they were making an awful noise (turbine-like) to the point that people were looking oddly at the van when I pulled into a parking spot. So yeah, the fans needed replacing. Oh, and I kinda trashed the fans when I pulled them out. (it took way longer than I expected and I did a bit of a victory dance with the assembly when I finally got it removed)

And the new fans are working fine when jumped, or with the the coolant temp sensor disconnected, so it's not the new fans.

So, thoughts?

unplug the fans then turn on the ac with a test light on the control side of the connector is there power and ground ? if there is then plug in the fans then on the fan side with a test light see if U get that same power and ground when its all plugged up U might have an aftermarket fan where the connections are not good and nothing is touching.

Crikey Gromit, you must have had a gut full of it by now. My sympathy.

Ignore AC for a minute. Did you say that the fans go on if you disconnect the coolant temp sensor (simulating a hot engine)? If so then that's a very positive test. How about then run the vehicle so its good and hot, air con off, then let it sit running at idle and wait for 30 mins...in that length of time, at this time of year, the fan should kick in based on hot engine temp. This assumes you have a thermostat in the system and that it works...if your temp gage shows approx mid range then that is the case.

If the fan does not kick in on a hot engine, but does kick in if you disconnect the sensor, that is pointing toward a bad sensor. Since you have renewed the sensor that is unlikely, but not impossible. See if you can determine what the resistance should be hot vs cold.

Now about the AC. In some vehicles the fan comes on whenever AC is selected, but in some vehicles, if the compressor does not engage then the fan does not come on. So have you checked that the compressor actually kicks in when AC selected? If you look at the pulley on the AC compressor, obviously it goes round whenever engine is running, but the central portion is stationary until the clutch engages when switched on...look at the pulley AC off and then AC on. Is the compressor actually engaging? If the compressor engages then for sure the fan should come on.

If you can establish that the fan works with engine sensor hot but not with AC compressor kicked in then you'll need to troubleshoot the AC system...that's beyond me I'm afraid.

Sorry if the above is just confusing you or if it sounds like I'm treating you as an idiot...as you know it is near impossible to indicate empathy in an e-mail. Good luck, don't give up!