2000 Grand Caravan 3.3 Cooling fans

[spectre09]

I have a 2000 Grand Caravan with a 3.3 engine. Problem is the cooling fans do not come on and the vehicle overheats. I put twelve volts to the plug on the fans and they do operate. Is there a relay or switch that turns these fans on, and where is it located.
Thanks in advance.
Mike Murphy

[neon_rt]

The fans don't simply turn on and off. I believe (but not 100% sure) that the + side is hot all the time (when engine is running) and the - side is grounded by the computer in a pulsed method that determines the fan rotation speed. There may be a relay for the + side of the fan in the relay box by the battery. Sorry I couldn't be of more help.

[vipergg]

Originally Posted by spectre09

I have a 2000 Grand Caravan with a 3.3 engine. Problem is the cooling fans do not come on and the vehicle overheats. I put twelve volts to the plug on the fans and they do operate. Is there a relay or switch that turns these fans on, and where is it located.
Thanks in advance.
Mike Murphy

Replace the radiator fan relay , these are a known problem on that era . On our 96 it is underneath the airbox , just a small little thing .

[B33p3r]

It's not a relay anymore, it's a Pulse Width Modulator. With that nonsense said.....The important thing to realize is if you check it with a volt meter you will not see a definate 12 volt signal. you'll probably see some movement on the meter but it won't be accurate. The fans fluctuate in speed now. Slower for less cooling and faster for more. If you had an "O-scope" (like everyone carries one in their back pocket) you could get a true picture of what's going on. It fluctuates on the + line. The ground is constant. Best advice which was already givin above is to change the Modulator(Relay), if no obvious wiring problems are found and the motors work when 12 volts are put to them.

[Mailt4]

This Relay is nothing like you've ever seen before, it is a Pause Width Modulated Relay, the ECU control this by grounded it and turns the Fans on in mitiple speeds, this Relay is available in some of your autopart stores, Dealers, it run about $80.00 around my hood, it is not in your Relay Box or look like your 4/5 pin Relay.
The Relay is located beside the Radiator on the Drive Side, behide Air filter Housing, it bolted in the radiator support , one connector/4 wires....not sure how to test it

Mai
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[Alexandra Spears]

Originally Posted by spectre09

I have a 2000 Grand Caravan with a 3.3 engine. Problem is the cooling fans do not come on and the vehicle overheats. I put twelve volts to the plug on the fans and they do operate. Is there a relay or switch that turns these fans on, and where is it located.
Thanks in advance.
Mike Murphy

Probably a relay. I had the same problem in my '97 GC (also a 3.3L engine). The fans would not come on--it would only stay cool if you kept moving and didn't have to stop.

Cost me about $300 parts and labor to get it fixed--I needed the fan relay replaced.

[zachr101]

I had the same problem. The fans did not go on even when engine hot. After chaging the cooling control sensor on top of the engine, I was told the relay is the problem It is not typical relay, it is solid state device something like 1.5 x 1.5 inch. plastic think, placed on aluminium heat sink and attached by 2 screws to the body of your van down under the air filter on drivers side and connected by plug. I was also told, that the frequent failing of this relay is because when A/C system malfunctions A/C pressure sensor is sending demand to the cooling fans (through this "relay" )for more cooling (A/C radiator is in front of Engine cooling radiator) and this "relay" gets overloaded and fails. Earlier models had regular contact relays, burning contacts and it was replaced by this contactless device, which obviously fails also. I bypassed the relay by switch and when in traffic or in hot days I help manualy to cool the engine by giving 12V to cooling fans. It is temporary measure, until my A/C unit gets fixed (if it ever gets fixed). I am not sure, if this is the only reason for the relais fail, but yes, I was told they replace it quite often. You may replace the relay easily by removing the air filter and unscrewing 2 screws holding the relay to the chasis of the van. Should you need the relay, I have bought 2 of them and would be willing to sell one. The number on the relay must be 04707286AF or AI (new part #).