Hello again,

2nd post in 2 years. not too bad lol...

Anyway after having my check engine light on for a LONG time, I just read about the odo displaying the code and tried it. Holy sh$t, it actually worked. So I got the engine code and looked it up and got this...

"P1491 Radiator Fan Ctrl Relay Circ"

Anyone know what problem this would cause? I have seen no ill effects in running. The only thing I believe may relate is my A/C only works when I'm moving, I can hear the fan click on and off quite frequently when I'm at a stop and the cab fogs up...

Aside from that, I'm lost.

Anyone?

 

I think you answered your own question. the realay for the fan is bad, so the fan isn't working, so you can't cool without the truck moving. what you're hearing isn't the fan turning on and off, it's the relay TRYING to turn on. replace the relay.

 

Ha ha ha. Really, it's that simple?

Geez!! Do you know the specifics on that relay?

 

it really might be that simple. sorry, I don't have a manual for your year/engine.

a way to confirm the problem would be to turn the AC on with the truck parked, see if you get any voltage at the fan. trace the wires up and see if there is voltage higher up the stream.

 

Well I went outside and tried the simple fix first. I noticed the 25amp fuse for the ac was shot, i didnt have a spare so for testing sake i pulled the 25a from the 4x4 module (I'm rwd so I figure that' ok for now) and I swapped the relay from the heated mirrors with the ac clutch fan relay.

After driving around for 2 years with a CEL and NO AC I can not believe that was all it took!!!!

In my defence, i had a friend who worked at a shop scan my cel when it first appeared and he said it was something to do with a fan relay but wasn't sure what it was and said to leave it which i did...What a clown!!!

Anyway I'm gonna run to Canadian Tire (canadian autozone lol) and grab some mini fuses and a new relay to replace the ones I 'borrowed"

now to replace the fog light fuse lol

 

Wonders never cease...

 

glad we could help. amazing what you can learn as an active member on a good forum, huh?

 

No kidding. I should have been posting on here from day 1. Oh well, I seem to be making up for it today as I've already quadrupled my post count....

Thanks again for all the help guys,

next on the list: Engine sludge cleaning (its getting pretty bad), TB cleaning, new shocks install (which will be in another post), tranny, rear end and cooling system fluid change.

Suddenly there is a new found love for the once thought lost ram....hooray!!!

 

you need to get on that engine sludge problem ASAP!!!!!!!!!!!!!!!!!!!

look up thread created by mmram23 (search his user name, you can click 'threads created by..." once you find his name). it was a 2 week long thread that nicely shows symptoms, diagnosis, and fix for sludge problems on the 4.7. it's a bit of a pain, but he did it in his driveway.

diff fluid change is in the DIY section. that's easy.

 

I've read his entire post and pm'd him. He hasnt replied but I'm pretty sure that if i follow his thread, it wont be to hard to figure out.

I am planning on doing that next week. It is first on the list.