What's burning out the radiator fan relay, 98 Grand Voyager 3.0?
 

When we bought the van a few years ago, the check engine light was on.
The diagnostic at AutoZone indicated possible fan relay, among other
things I had to fix. Replaced the relay, fans worked fine for 3
months, Same thing, got a relay from a dealer this time, 3 months or
so, I'm replacing it for the 3rd time. What's causing it to burn out?
The plastic on the connector at the pin 1 ( ? ) contact is a bit
melted. Help! These relays ain't cheap...
Mark Goodall

What's burning out the radiator fan relay, 98 Grand Voyager 3.0?
 

On 9/4/2011 8:40 PM, mark wrote:
> When we bought the van a few years ago, the check engine light was on.
> The diagnostic at AutoZone indicated possible fan relay, among other
> things I had to fix. Replaced the relay, fans worked fine for 3
> months, Same thing, got a relay from a dealer this time, 3 months or
> so, I'm replacing it for the 3rd time. What's causing it to burn out?
> The plastic on the connector at the pin 1 ( ? ) contact is a bit
> melted. Help! These relays ain't cheap...
> Mark Goodall


Yes, they are pretty cheap. Like $12. But it is the fan that is
throwing the voltage out of whack. It's easier just to use the single
speed fan than replace all.

What's burning out the radiator fan relay, 98 Grand Voyager 3.0?
 

"mark" > wrote in message
...
> When we bought the van a few years ago, the check engine light was on.
> The diagnostic at AutoZone indicated possible fan relay, among other
> things I had to fix. Replaced the relay, fans worked fine for 3
> months, Same thing, got a relay from a dealer this time, 3 months or
> so, I'm replacing it for the 3rd time. What's causing it to burn out?
> The plastic on the connector at the pin 1 ( ? ) contact is a bit
> melted. Help! These relays ain't cheap...
> Mark Goodall

This is a WAG (wild a**ed guess) but check the current drain on the fan. I
expect that it's marginally just below failure and the added current is
melting the relay housing.

What's burning out the radiator fan relay, 98 Grand Voyager 3.0?
 

"mark" > wrote in message
...
> When we bought the van a few years ago, the check engine light was on.
> The diagnostic at AutoZone indicated possible fan relay, among other
> things I had to fix. Replaced the relay, fans worked fine for 3
> months, Same thing, got a relay from a dealer this time, 3 months or
> so, I'm replacing it for the 3rd time. What's causing it to burn out?
> The plastic on the connector at the pin 1 ( ? ) contact is a bit
> melted. Help! These relays ain't cheap...
> Mark Goodall

They aren't relays at all, the rad fan on 3rd generation Chrysler vans are
all variable speed and what they call a "relay" is actually an electronic
PWM motor speed controller with a big power MOSFET in it. If it is
overheating the fan is likely overamping or the "relay" might need to be
bolted to something that is better at getting rid of heat, like an old
computer CPU heatsink.

What's burning out the radiator fan relay, 98 Grand Voyager 3.0?
 

"Daniel who wants to know" > wrote in message
...
>
> They aren't relays at all, the rad fan on 3rd generation Chrysler vans are
> all variable speed and what they call a "relay" is actually an electronic
> PWM motor speed controller with a big power MOSFET in it. If it is
> overheating the fan is likely overamping or the "relay" might need to be
> bolted to something that is better at getting rid of heat, like an old
> computer CPU heatsink.
>

I just looked on fleabay and noticed that the ones for the 4th gen vans have
a PGA (pin grid array) heatsink on the back, kind of like, you guessed it, a
CPU (processor) cooler heatsink. It would appear Chrysler learned something
and quietly made a change.

What's burning out the radiator fan relay, 98 Grand Voyager 3.0?
 

It appears it's not the 'relay' this time. I replaced it ($58) and the fans wouldn't work, running the van up past normal temp. I should have known, because last time the check engine scan threw a code for it, and this time it didn't. As Daniel indicated, it's not a relay, so I don't think I can check it with a VOM. The fans run fine straight off the battery (although one fan has a bit of resistance when I turn it by hand)so I'm thinking about wiring them to the battery and fuse box so they only run with the key on. I think the fan wires are green & black, anyone know the polarity so they spin the right direction?
Mark Goodall

Radiator fan relay, 98 Grand Voyager 3.0 L, continued
 

It appears it's not the 'relay' this time. I replaced it ($58) and the fans wouldn't work, running the van up past normal temp. I should have known, because last time the check engine scan threw a code for it, and this time it didn't. As Daniel indicated, it's not a relay, so I don't think I can check it with a VOM. The fans run fine straight off the battery (although one fan has a bit of resistance when I turn it by hand)so I'm thinking about wiring them to the battery and fuse box so they only run with the key on. I think the fan wires are green & black, anyone know the polarity so they spin the right direction?
Mark Goodall

What's burning out the radiator fan relay, 98 Grand Voyager 3.0?
 

Mark Goodall wrote:

> The fans run fine straight off the battery

You might was well connect the fans directly to the battery (or to the
switched 12V bus that becomes active when-ever the ignition is on).

> although one fan has a bit of resistance when I turn it by hand

You need to oil or lubricate that fan - or replace it. That sticking
fan is drawing more load from your electronic relay, which is causing
your relay failure.

> so I'm thinking about wiring them to the battery and fuse box so
> they only run with the key on.

But you need to lubricate that fan so it turns freely, otherwise it will
eventually fail.

What's burning out the radiator fan relay, 98 Grand Voyager 3.0?
 

Thanks Mopar Man, how do I know I've got the fan polarity right? Blowing toward the engine?
Mark Goodall

What's burning out the radiator fan relay, 98 Grand Voyager 3.0?
 

Mark Goodall wrote:

> Thanks Mopar Man, how do I know I've got the fan polarity right?
> Blowing toward the engine?

Well, first of all I would expect that one lead of the fan motor is
already connected to ground - because there's no need to switch BOTH
leads of the fan motor - just the hot or +12V lead.

If that's not the case, or if you can't identify the switched or hot
lead, then yes, the fan normally pulls (or pushes) air from the front of
the car through the radiator towards the engine block.