Question about 1999 Plymouth Grand Voyager
Most likely it's a bad radiator T/S (Thermal Temp Switch or Sensor). There may be more then one however, so both need to be checked properly!
Read the below prior post I sent a guy on his similar Jeep radiator fan problem as it should help you to pinpoint the bad Sensor.
The fan doesn't work. Replaced the fan motor today and still not working. Could it be a problem with the relay switch which, I believe, is under the passenger side head lamp assembly?
I answered a similar ? at Yahoo Answers awhile back, and it solved that person's problem on their 1987 Jeep.
Seeings a new fan motor didn't solve the original non-op problem we can definitely establish that the old fan being bad really wasn't bad at all and NOT the problem to start with.
As with any 12-volt DC automotive motor (whether for the radiator cooling fan, windshield wiper motor, interior passenger compartment cooling/circ fan, etc) a simple disconnected from the car's electrical system test should have been done 1st to make sure the old fan motor was really bad. Too late for that now though. I myself would have seriously doubted that a 6 year old fan motor would have been bad already.
If you had no recent engine or radiator related mechanical work done to the Jeep - as of late - then the problem may not even be a bad wiring harness connection, but you never know.
If all the radiator fan Temp related Sensors & Thermal Switch connectors are properly seated then we need to look at yet another possibility having eliminating a wiring connector type problem.
On most radiators with an electric assist fan(s) there is also an electric Thermo Sense switch (TS) mounted on the radiator itself that has to be working properly otherwise this fan switch could stick in the CLOSED position (set point usually 190 degrees F) leaving the fan to run all the time while the engine is running. Make sure it is connected as to the wiring connector, as I've seen this connection get pulled apart from other engine related work being done or else from a bad connector itself.
If this TS goes bad and someone disconnects it so as to stop the fan from running all the time - then it may look like the fan itself is bad when it really isn't.
On the other hand this TS switch could actually stick in the OPEN position (though this is very rare with this type of Thermal switch), and then the fan wouldn't run at all, and the engine would probably run HOTTER then normal as a dead giveaway. If your engine is running HOTTER then normal I would go directly to this TS and check it for proper operation. It's usually mounted on the radiator fan bracket nearest the radiator with a separate 2-wire wiring connector.
If it's working properly - when the ignition is turned off - the fan should still turn off as it is usually controlled by a timed RELAY circuit as a failsafe. Does it??
Hopefully you don't have any engine cooling problems to start with, but if you do follow the guidelines below:
If the engine thermostat is sticking CLOSED, or indeed stuck CLOSED, that could also cause the fan to run excessively. Running plain water in the engine and not proper 50/50 antifreeze/coolant mix can also cause the engine to run much hotter then normal and thus adds to running the radiator fan more frequently then normal.
Excessive radiator fan running leads to just one thing, and that is worn out bearings. Some of these fans aren't made that good to begin with!
If the fan is indeed 'tired' or has a tendency to try and freeze up there should be safeguards to prevent wiring from burning up.
Most radiators have 2 thermo-switches (TS), one being an ambient radiator surface mounted TS, and the other one being an internal (screwed into) radiator mounted TS. There might even be a 3rd fan TS that is clipped directly to the fan motor case itself to sense an over-temp situation like that from the fan bearings freezing and the fan itself running hotter then normal. Just depends on car maker design.
There is also a TIMER RELAY module incorporated in all CA equipped cars as part of the SMOG packaging for cars sold here in this state. Reason for that is to reset the pre-warm circuit properly when restarting the car back up after shorter run and stop trips. If this relay is bad it could cause the fan to run on longer then normal after shutting off the vehicle, thus causing undue wear and tear on the fan motor also. I used to think it also helped to clear out any fuel fumes from under the hood after running the engine, but could never prove it or have it verified by my own minivan maker when I owned a minivan??
NEVER DRIVE THE JEEP WITHOUT THE FAN MOTOR BEING CONNECTED!! You will surely damage something you don't want to!!!
To check the radiator fan circuit do the following:
I would first disconnect the battery from the circuit, and do any resistive type DVM meter checks first (unless you are unsure of how to do them), and then do the following checks below to check out the fan motor and related sensors/switches with power reconnected. If you have a lot of MEMORY type devices onboard your Jeep (Stereo, GPS, etc) you might want to use a simple 12-volt TEST LIGHT or again a good DVM to trace for a good ~12-volt battery voltage at point-to-point connectors instead, so as not to lose those memory settings.
First check the wiring leading to and from the fan motor itself and the TS (1 or possibly 2) connectors to make sure they are snapped together fully and making good connections. Also check the GROUND WIRE coming off the fan motor connector - as if this ground point is dirty or corroded causing a bad ground return path then the fan motor will appear to be dead as well.
Next check the fan itself for free-play. Is it turning freely or is it very tight or hard to spin?? If so - you have a bad fan and it's time to replace it NOW! (In your case it doesn't appear to be a bad fad fan motor at all.)
If you are handy with a digital volt meter (DVM) connect it in DC series with the fan motor and while running the Jeep measure the current and compare it to a new fan's rating. If it's excessive then the fan motor is on it's way out. Time to replace. (Skip this part too, as your fan is known good.)
VERY IMPORTANT STEP HERE - Also check those 1 or 2 TS switches to make sure they are in the OPEN setting with a COLD engine/radiator. CHECK AGAIN to make sure they CLOSE at the proper engine temp as well. If they don't close at or near 190 degrees F then one or the other (if there are 2 or more in your system) may be bad, and that may very well be your only problem.
If Jeep has added a FUSE or FUSIBLE LINK to the fan circuit make sure you check that part also. It's doubtful though, as the fan circuit is fairly simple by design. A Timer Relay type Switch would be downstream of the/any TS switch(es) by design as well, so I would place my money 1st on a bad TS switch, or a possible bad ground connection 2nd.
Does not appear to be anything else that excessive as it looks to just be isolated to the radiator fan circuit itself.
Hope this helps you out to troubleshoot the problem. Feel free to email me if you still have further ??'s.
AND THEIR REPLY WAS:
posted by djvanh on Aug 13, 2008
We are being told that it is the PCM that is causing the fan not to work. Can we replace the PCM with a remanufactured one?
AND MY REPLY WAS:
I guess I better ask you a couple of ?'s before going any further here - as I'm not getting back any feedback at all as to what I posted previously.
No past history - no past to present attempted fixes - no troubleshooting feedback.....
The reason I say this is because now you are saying > We are being told that it is the PCM that is causing the fan not to work.
This has me asking - WHO is telling you that the Powertrain Control Module is supposedly bad? By WHO I mean - Jeep dealership - auto repair garage - your friend - who?
I need to know what steps you took to get to this new revelation point - as to the fan supposedly not working?
Please be very specific, and not just a 1 or 2 line reply - as that won't help me pinpoint the problem at all. After all - you have the SUV there (wherever you are located state/city wise), and I don't.
Also - do you have the/a service manual (Haynes or Chilton Auto Manual for your year & make Jeep)?
When I get your feedback we can proceed forward.
1 - Highly degreed in Electronics first of all.
2 - Worked for 2 SEARS AUTOMOTIVE STORES, one on the East Coast and the other one still being the largest SEARS AUTO in CHICAGO at 6-corners. I specialized in troubleshooting all auto electrical problems - including battery testing and charging system testing and repair. Graduate of DeVry in Chicago also!
3 - Troubleshooted, repaired, and replaced many water pumps, thermostats, fans, TS units, and radiators on all types of vehicles and makes and models. I hate those stupid internal water pumps on many of the *** Honda and similar autos as that is the dumbest design I've ever seen! Stay away from buying one of these headaches!! Timing belts (non-metal type) are just as bad!
Posted on Aug 21, 2008
Im guessing that the van is overheating in the traffic. you are going to need to have someone with an OBDII scan tool look at it the PCM controls those fans when the coolant temp sending unit tells the PCM the temp is so that the PCM needs to command on the fans, Has anyone changed the cooling fan relay?
Posted on Aug 21, 2008
There should be a relay controlling them, check the relay comm for power.. You can connect the radiator fan driectly to the battery to prevent over heating. It has two wires, splice them and connect them to the battery via 2 other pieces of wire. In my opinion its very difficult to actually help with this one remotely since we would need to be on spot to test the circuit. I strongly suggest haveing an autoelectrican check this for you. YOu can connect the radiator fan directly to the battery to help you get there..
BTW the radiator contains a thermostat. this turns the fan on and off, of this is faulty you will have the problem you described. check the thermostat in the radiator.
Posted on Feb 07, 2009
there's a sensor on the radiator that tells the fan to come on a serten temp,replace that,there normally on the side,just release the clip and pull it out,make sure it cold before you remove it as the water will come out.
Posted on Dec 24, 2009
Change the thermostat and bleed the ir from the cooling system,then ,if the cooling fans do not come on,check the relay module under the cooling fans on drivers side,they are bad to go out,but if there is air in the cooling system,the cooling fans will not come on.
Posted on May 31, 2010
Tips for a great answer:
Mar 16, 2014 | Cars & Trucks
Nov 10, 2013 | Mitsubishi Lancer Cars & Trucks
Sep 03, 2011 | 2000 Honda CR-V
Jan 30, 2011 | 2000 Dodge Caravan
Jan 08, 2011 | 2002 Chrysler Town & Country
Jun 08, 2010 | 2002 Mitsubishi Galant
Dec 24, 2009 | 2000 Daewoo Leganza
Apr 24, 2009 | 1991 Buick Century
Apr 08, 2009 | 1998 Ford Mustang
Feb 15, 2009 | 1991 Honda Civic
1,450 people viewed this question
Usually answered in minutes!
Step 2: Please assign your manual to a product: