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A/C Condenser Fan won't work (new fan motor)

26K views 24 replies 4 participants last post by  RamTech 
#1 ·
I've replaced both the relay and the condenser fan. It turns out that the fuse block has a short in it preventing the condenser fan from kicking on. The maintenance shop wants $500 to replace the fuse block but I don't want to drop more money into it. I've heard that I can just use a jumper wire but not sure how to do it....any ideas? Thanks!
 
#2 ·
First, welcome to the forum since I see you're new here! Unfortunately I don't have an answer to your question, but this will bring it to the top again so those who can help will see it, but good luck and someone should be along shortly! When you get a chance, be sure to introduce yourself to everyone in the Newbie Checkin and get your official Ram Z welcome! :)

- Cajun
 
#8 ·
The condenser fan relay is 39. Since the fan will not turn on (it is a brand new fan) and the mechanic told me there was a short in my fuse block, I assume that the short is affecting relay terminal 39. He unofficial told me I could jumper the the short instead of spending the $500 but didn't tell me how to do it. I'm trying to trade the truck in and don't want to drop more money into it then I have to. Is there anyway to take the fuse block apart and fix the short? I'm not sure if it is meant to come apart but I willing to try it. Thanks!
 
#10 ·
I was referring to the actual terminal numbers on the relay itself. Terminal 85 should be hot with the key on and 86 is controlled by the PCM to supply a ground and close the relay contacts. Terminal 30 should also be hot with the key on and power will flow out of terminal 87 to the fan with the relay contacts closed.
 
#11 ·
I see. That is good to know when i go out and test the terminal myself. With that info, I can figure out which terminal is bad on the relay and how to jump it. I'll go check each terminal and post the results. Thanks for your help and patience on this.

Matt
 
#12 · (Edited)
I just tested the relay. Without the A/C on, there was power applied to terminal 85. Based on the normal relay operation, terminal 85 should only have power if the A/C switch is set to on. Terminal 30 should have power applied from the battery all the time. This terminal did not have power. The way I understand it, Terminal 30 supplies power from the battery which is only sent to the output terminal, 87, when terminal 85 is energized by turning on the A/C. Now what does it mean if terminal 85 has power w/o the A/C on but terminal 30 does not have power? Is there a short between the two? Can I open up the fuse box and fix the short? Can I use a jumper to fix the problem? I hope this info clears the situation up. Thanks!

Matt
 
#17 ·
Forgive my ignorance, but what is the IPM? My mechanic says there is a short in the fuse box. Could there be a short within the box itself? A chewed wire is possible and I will check that.

Would it be better to just bypass the relay and wire the fan up to the ignition? I don't mind if the fan is on whenever the truck is running. It doesn't need to shut off until the truck shuts off.

Thanks!

Matt
 
#19 ·
Will connecting the fan to an Ignition source, so it runs whenever the truck runs, place undue load on the alternator?

I see there are spare relay terminals in the IPM. Could I wire the fan to a spare terminal? I assume all relay terminals are built the same and as long as I wire it up right, one terminal is as good as another...is this accurate? I'm just trying to find the best alternative to fix this problem without creating more problems. Thanks!

Matt
 
#22 ·
Ok, so on my late 80s model vehicles I could tie into the ignition system by wiring right into the appropriate fuse. Dodge uses mini-fuses which are impossible to run a wire into. How else can I wire my a/c condenser fan into the ignition system so it runs whenever the truck is running? Thanks in advance for any help you guys can give on this!

Matt
 
#23 ·
Splice into the DB/BK wire on the compressor clutch and run it to terminal 85 on the relay. Run a ground wire to 86. 18 gauge wire will work fine for these two terminals. Pull a fused battery feed wire (at least 12 gauge with a 25 amp fuse) to terminal 30 and then splice the power wire to the fan into terminal 87. I strongly recommend soldering the wire to the spade terminals that plug into the relay or get a relay pigtail and solder the splices there.
 
#24 ·
Randy,

Thanks for the instructions. I found an unused relay inside the fuse box that i wired into. I put a male connector on the fused wire and plugged it into the terminal that got power when the ignition was on. I ran a ground wire to the frame and now the system is up and running. I will try your instructions this weekend but needed a quick fix for now to get me by. Thanks for your help!

Matt
 
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