Overheating......Radiator Fan Not running... Help - Page 3

Al_K · 10-07-2004, 03:20 PM

My 94 Plymouth Voyager (4 cylinder) temperature occationally indicates overheating condition, maybe on 1 out of 10 trips. Most trips ,25 miles or so, are without event, but sometimes after 5-10 minutes or so the temperature gauge pegs and the gong goes off. After 1-2 minutes the temperature gauge returns to normal and doesn't indicate overheating the rest of the trip.

So far, this is what I've found out and what I've done to resolve the problem. I've discovered 2 sensors that are involved.

There is a temperature sensor, ACDelco part # C1860, located on the lower portion of the block just below the second spark plug. This part is about 2" long and has a single screw terminal at the top with a single wire connector which can be pulled off. Cost $13.99
See http://www.acdelco.com/html/catalog/index.htm
This sensor drives the temperature gauge and does NOT drive the fan. The wire, when grounded , will peg the temperature gauge but the fan does not come on.

The second is a coolant sensor, Mopar # 33004281, located just below the thermostat behind the igrition coil. This part is also about 2" long but has a locking device on a 2 wire connector. Cost $58 at dealer and $14.95 on Web. See http://www.xtremeterrain.com/p90.htm
This sensor drives the fan via the relay circuitry. When this connector is unplugged, the low speed fan runs, although the check engine light show code #22, coolant sensor "out of range or disconnected". I don't believe this is a problem but looking for comments.

As a side issue, the relays are located in a box on the driver's side wheel well under the hook. The "box" is about 3" by 4" with a locking tab. On the inside cover is shown the relay identification and fuse location. When looking from the front of the van and directly over the computer box, there are 2 columns of relays, the left has 4 relays and the right has 2. The radiator low fan has a 25 amp fuse.

Computer, Relay and Fuse Box

----------------------------------------------------------
|
| FUSES including 25 amp low radiator fan fuse
|
| High Fan Radiator Ground Relay
| Fuel Pump Relay
| Low Fan Radiator Relay Air Cond Clutch Relay
| Auto shut down Relay High Fan Radiator Relay
|
|-----------------------------------------------------------

Front of Van

At this point I'm operating with the temperature sensor connected, (temperature gauge operational) and coolant sensor connector unplugged which causes the low fan to run when the engine is running and living with the check engine light, code #22. This is a cheap fix and may indicate a bad coolant sensor, and I need to replace it. If the overheating reocurrs, I'm planning on looking at the temperature circuit for bad temperature sensor or bad temp gauge. Comments?

slo · 10-07-2004, 03:52 PM

I have a 97 T&C with 3.8 AWD and had the same problem. I changed the thermostar (easiest first) no help, I removed the fan abd tested it with direct current worked fine, then I changed a sensor no help, then I had to do a head stand and grow another hand to change a relay on the front of the engine compartment at the side of the radiator, WALLA! Got the sensor from the Chrysler dealer and just a simple plug in for electric change over. Don't know if this helps but it took me about 2 weeks to find the **** relay next to the radiator.

wightj · 10-12-2004, 08:36 AM

Quote:

Originally Posted by 3rdOne

Great forum...by the way!!

93 Ply Grand Voyager SE 3.3L V6
Drove about 10 miles yesterday van ran fine. Stopped in a parking lot left van running. Check gauge light came on. Van was overheating. Coolant level was fine. Radiator fan would not run. Drove it back home temperature gauge stayed were it always did on drive home. Left it running in driveway it began to overheat. Checked fan it is operational just won't kick on.

Any advice???

A/C compressor stopped running a couple weeks ago could they be related problems? Relays Prehaps??

There is a sensor located (on 1997) on the drivers side down by the radiator. It is hard to find, but just follow the wires that are next to hte radiator. This sensor is about 60 bucks but usually is the cause of the problem.

ssixs · 11-28-2004, 06:32 AM

My cooling fan stopped working in my 96 Caravan awhile back. Took it to the dealer and guess what, there was a recall on a faulty fan control relay. They fixed it (no charge) and never had the problem again.

jgionet · 11-29-2004, 12:13 PM

I'm having the same problem too.. (96 3.3 Caravan) Rad fan isn't kicking on when temp rises. I already replaced the thermastat so I'm guessing it's the temp sensor Bigjohnjr replaced. I did unplug my A/C compressor as even though I had it off and I wanted heat the compressor "seemed" to be still running. (is that normal?)

casa01 · 12-15-2004, 08:04 PM

I have a 97 caravan and the fans stopped working.I looked for the relay and could not find one .after many tries,I found out it uses a solid state relay which is a small square on the inner fender and that fixed the problem. cost of relay $56.00 and it does not look anything like your typical relay. Hope this helps someone out there.

jgionet · 12-16-2004, 08:09 AM

would you happen to have a part number for that relay? or a better description so when I call my parts people they know what I'm talking about.

thxs

Spit · 12-16-2004, 11:18 AM

My 1997 Grand Caravan had the same problem. I replaced a solid state fan relay that cost about $70. it was located near the radiator on the
drivers side below the battery etc.

Spit

casa01 · 12-16-2004, 03:46 PM

I do not remember where I left the receipt, but I just asked the guy @ the counter(bumper to bumper ) and he ordered me one.
you can also call a dodge dealer and ask them for the part numer or better yet go there and they will pull a pcture of the relay and its location so you can see it(it is located on the inside wall bellow the battery and next to the bottom of the radiator,,,it is square and the wires dead end there with another harness going to yhe fan wiring harness.you wont miss it if you just follow the wires from the fans.
Good luck and let me know if that helped.

fred barney · 12-21-2004, 03:28 PM

I bought an 89 Voyager that was overheating because the fan wouldn't kick in. I checked the fan motor, coolant sensor, and relays and found that they were all good.

Then I noticed the fusible link was burnt out so I replaced it (not as easy as it sounds). It immediately started to heat up again with the van running.

I traced the wires to the AC fan and found that it was loose on the shaft due to wear. Went to a junk yard and bought a good used one and it FIXED THE PROBLEM.

What a lousy circuit design! An accessory component goes and it disables your vehicle and can burn up your engine.

dacrums · 08-28-2005, 10:58 AM

Anyone who hardwired their fans....

What did you use as the power source? Where is there a switched power wire?

Thanks

ecfune · 08-30-2005, 07:04 PM

Have a '96 Grand Caravan that had the same problem before - the fan will not kick in and it overheats. I replaced the fan sensor and it solved the problem. A few months after, Dodge came out with a safety recall for the sensors and I got my money back for the parts that I purchased prior to the recall.

ecfune · 08-30-2005, 07:09 PM

Correction - it was a fan relay and not a sensor located underneath the fender wall and radiator.

brunswick · 03-18-2006, 12:30 AM

Hi,

Hope I've not missed any relevant posts on this. My problem similar to what I've read. Make and model 1997 Chrysler LHS, 3.5 Liter engine; two fans; two speeds (two relays in module on L.H. side on fender).

Overheats when not at highway speed (stop-and-go or idle). Have confirmed that fans eventually cut-in, but too late to cool engine to proper level. Used to be intermittent, but now pretty consistent.

Have traced as follows:

Replaced relays.
Shorted lo-speed relay primary to ground - both fans run at lo-speed.
Shorted hi-speed relay primary to ground - both fans run at hi-speed.
Traced wire connection from computer module to both relay primaries - both good.
Traced wire connection to engine coolant temp sensor - good.

My chrysler FSM (Factory Service Manual) for this car indicates that Temp Sensor signal controls both temp guage on dash AND cooling fan operation. Since guage shows a rise in engine temp, should also turn on fans I would think (but doesn't). This is why I haven't replaced coolant temp guage.

Dealer just wants to sell me diagnostic time and then talks all the usual BS (flush the system; change the thermostat; etc. etc.) I KNOW the fans are the problem not the cooling system!

Am thinking of wiring toggle switch on dash to short relay return line to ground but that's just my frustration showing. I'm hoping SOMEBODY knows a LOGICAL explanation.

-Hank

Stevo2 · 03-20-2006, 02:01 AM

There's really not a whole bunch in that circuit. PCM monitors the engine temp with voltage readings from the coolant temp sensor. I's the PCM's job to select fan function based on engine temp.

I would replace the sender/sensor and check the ground for the radiator fan assembly. Some vehicles have 2 sensors...one for the fan and one for the computer/gauge...I'm not sure if yours is set up that way?
The sender works on variable resistence(temperature dependent), this provides a varying voltage to the PCM which it uses to control the fan and the rest of the engine.

Do the fans go on when you turn the A/C on?

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