Fan Relay???

[Papo]

I have a 98 Grand Caravan that overheats due to radiator fan not functioning. I removed the fan relay to test and found that it isn't a conventional electro-mechanical relay but an electronic one. Can anyone tell me if this relay can be tested and if yes, how? Also I tried to test for the voltage coming the PCM which triggers the relay and could not get a voltage. What should should be the voltage from the PCM. The cooland sensor seems to be working as the gauge on the dash is working a the booby light comes on when coolant is extremely high. Also
turned on air and fan didn't come on. Checked wiring continuity in fan & relay circuits and they are ok. I'm using a fluke DVOM. I'll pay the 86.60 the dealer is asking if I were 100% sure the relay is bad. Thanks for any help

[Mrbizness1]

The dealer replaced the fan relay when my 98 was less than a year old under warranty. They said Chrysler changed the specs on the new one.
A few years later I had to replace it again because the fan wouldn't come on for the a/c. $86.60 sounds high, I think I paid about $50.00
or less. I am talking about the relay that bolts on the left front frame.
I don't know if there are any others on the vehicle.

[B33p3r]

The 2001's have a pulsed signal sent to the relay from the PCM via the IPM. This pulsed signal makes your fan a variable speed motor. A long story short.......You probably won't see any set Voltage on the relay control. This is why your relay is solid state as opposed to mechanical. Solid state can switch on and off(pulse) much faster.
Jump 12 volts directly to your fan. Does it work?
You didn't mention checking the fuse for your fan.
Is your coolant temperature sensor working? You said your dash temp gauge works...however there are sometimes 2 seperate sensors for coolant temp. 1 for the dash and another for the pcm.
Also check the ground for your relay. Disconnect and clean it up.
trace you wiring back to the pcm from the relay. If all the above is ok, it's either the relay or a PCM problem. I'd go relay first. One other thing you can try is to disconnect battery for 10 minutes to reset the modules, just in case they are locked up.

[yogi_123rd]

You have two seperate temperature sensors. The one that controls the radiator fans has two wires in the connector because it is a switch. When it gets hot, current goes thru the switch and activates the fan relay. This switch is located near where the thermostat is and measures the temperature of the water coming from the radiator. If you jump the wires in the two wire connector of the switch with ignition on, the radiator fan should run. If they do, the relay is good and the switch is likely faulty. If they don't, the relay or a fuse is likely bad.

The other sensor has one wire in the connector and is used strictly by the temperature gage.

[1thunder]

yogi you are right but you dont have to jump the wires to make the fan come on all you have to do is disconnect the 2 wire coolant sensor when engine is running fan is programed or defaulted to go on when loosing coolant sensor signal. Also you need 12 volts at i think the gray 14 gauge wire at the relay no volts at relay no fan

[Papo]

First I want to say thanks to all that have responded. Will try to respond to all ???. Mrbizness1 - I went to the dealer and inquired about recalls for the 98 caravan. Records show that I had taken the van in for the "Relay" a month after I bought it in April of 98. Just my luck, they fixed it when it wasn't broke. B33p3r,yogi_123rd,1thunder - Seems like over engineering to me. Makes it difficult to test the relay when you're not sure what activates it. The fans worked when I shorted the terminals (3&4) on the relay connector. The only coolant sensor I've found is the one by the thermastat. When I remove the connector the fans did not turn on but the guage stop indicating the temperature. I also turn on the air conditioning and fan still didn't work. The 40 amp. fuse is good. I tested the wire from the relay to the pcm as suggested and it tested ok. So, based on my lifelines my final anwser is the fan relay. It'll receive it this evening. Will let you know. Thanks again!

[Papo]

I put in the new fan relay. With the air conditioner running the fan started working within a matter of minutes. Thanks for all the help!

[hanki]

i had the same problem and i replace the relay , it works , the question is why this relay burnt, i wonder if someone can help , i m thinking about fan are pulling too much current.
another possibility i noticed that on the book oh haynes , there is an optional engine block heater that should be installed between the radiator and the motor , it dont exist on my car , is it possible that due to the non existing of this block heater, fan are getting too hot and pulling too much current from the relay?
any case , this site and all your discussion wrere very helpful , i saved a lot of money , thanke for AF , anf for you guys...