Trying to figure out how the radiator fan should work, specifically the high speed relay. According to rockauto and every other part lookup I have tried the high speed fan relay is a solid state relay aftermarket type SMP RY-446. But I found other sources that show a mechanical relay and under the hood it looks like my van has one of those. Any idea what the type number of that relay is so I can order a replacement? The van is a 2008 T&C LX (24G) with 3.3L engine and front/rear AC.

See the schematic and diagram below, and unless I am missing something, there is no solid state relay in my van even though all parts lookups say it has one:

 

"Relay-Radiator Fan High Speed" is the relay you're looking for and is depicted and labeled as such in the second diagram. Looks like it's mounted just inboard of the driver's headlight assembly. Find it then verify by matching the wire color identification depicted in your wiring diagram to the wiring at the relay connector.

When all else fails swing by your dealership and ask them to show it to you.

 

I think I found the high speed relay, right where the diagram says it is, just inboard of the drivers side headlight. It looks like a plain old mechanical relay, no heatsink. So all the parts lookups must be wrong and this van does not have a solid state relay?

 

Whats the part number stamped on it?

 

It's a 56007078.

I took the relay off and tested it, works fine by itself. Applied battery voltage across terminals 85 (+) and 86 (GND), heard it click. The normally open terminals 30 to 87 closed, and the normally closed terminals 30 to 87a opened.

With the relay still out of the van, I put my multimeter in the van relay connector across terminals 85 and 86. Turned on the engine, and the multimeter went from nothing to 12.8V, which is a bit surprising, because the fan wouldn't be expected to turn on high speed when a cold engine is started and the AC is off. I tried jumpering the connector from pins 30 to 87 and the radiator fan turns on at high speed. Turned off the engine. Reinstalled the relay. Turned on the engine, and the fan does not turn on even when the AC is on. Grrrrr.

 

Yup, looks like that relay is used on numerous systems. That click says it's not the typical PWM fan relay found on earlier generation vans as you well know. Looks like you have bigger problems maybe PCM related and I see now on 5th gen vans it appears the PCM controls the fans over the CAN data bus - yuck. To my eyes you almost have to use a DRB scanner to verify the PCM is the culprit. Short of that you could run continuity checks on the wiring from the TIPM to the relay and check for damaged pins.

Odd that the WD shows the relay pins are labeled 1,2,4,5 but the you're finding the typical 30,87 etc. (????) The wire ID colors matched up right?

Hey Tizzy1. Are we looking at this right? Did Chrysler do away with the PWM relay on the 5th gens?

 

That's starting to sound like a $1000 repair at the dealer

I think I am going to add a wire to the AC indicator light by the AC on/off switch, run that signal through a transistor buffer circuit to create a 12v control, and OR diode it into the radiator fan high speed relay control. Maybe $2 and an hours work.

By the way, I took the relay numbering off the body of the relay.

 

Update: still confused, but the AC is now working. For one, my AC manifold gauges are messed up. I went to recheck the low and high side pressures, and couldn't get a sensible high side reading. Then I noticed the collar on the quick connect was jamming. By the time I had messed around with the connect and lost a lot of gas, decided to vacuum the system and start with a known baseline. Filled the system and got nice cold air out of the vents. Still the radiator fan wasn't on. Left it idling with a hot engine and the AC running, and after about another 10 minutes the radiator fan clicked on. I'm thinking it turned on because the engine was getting too hot, rather than anything the AC was doing.

Yesterday I went out to the van and it was reading 100F on the dash readout. The meat thermometer in the center vent read maybe 110F. Started the engine and went for a drive. The vent thermometer dropped over a minute or two down to 60F. Clicked the recycle button and it settled down to 50F. The van temperature readout still said 100F, then it clicked to 101F. So I get a good 40F differential from the AC now, and 50F in recirculate mode. I still think the radiator fan control is messed up, but now the AC is cold, I'm going to let it be.

 

"I still think the radiator fan control is messed up, but now the AC is cold, I'm going to let it be."

Progress at least. As for me, I can't recommend anything until I find a narrative or someone lets us in on how the rad fan system works on 5th gen vans. Apparently changes were made (no PWM relay) making them functionally different from 3rd and 4th gen vans which were functionally nearly the same. Logic tells me the A/C pressure switch isn't doing it's job but that's based on 3rd, 4th gen knowledge. Until then I hope you get your answer.

 

I am just getting into this issue on a 2005 T&C, but I will say that it seems that the female terminals do not sit very well in the plastic connector that snaps to the relay. In the particular the smaller control wires seem to easily back out and thus not make contact with the pins on the relay.

I just bought the van and the bumper had been replaced, so I had to remove the relay from the old bumper frame and install it on the new. I am thinking that the relay having been connected and disconnected several times has affected how snugly those terminals fit in the connector. Jiggling them seemed to help. I ended up having to do something else, so I don't have any definitive answer yet.