Just finished a pretty good search and still can't find anyone who has experienced this problem.

After a few weeks of battery being disconnected (out of town vacation) I fired up my car and came to find out that my radiator fans are not coming on to high speed ( I noticed this because water temps on my PFC were higher than usual. Then today I tried to get them to come on by turning on the AC but then I noticed they weren't on at all and temps were rising! I shut it down and found that the cooling fan fuse (40A) was blown. Not sure weither this happened before or after I tried the AC.

So I was wondering if anyone else has experienced this problem? I'm thinking either a short or even fan motor might be going bad? Any help or suggestions greatly appreciated before I start digging into the entire system. Thanks, Jerry

 

It's obviously a ground fault of some sort, but you might want to just replace the fuse first to see if it blows again. It could be any number of things: wiring near relays exposed, fan motor wiring worn/exposed, etc. A fan motor "going bad" usually won't blow a fuse; the motors are wired in parallel, so if one goes out, the other still functions.

 

Well they both still funtion, it's just that they only seem to come on low speed. By the way do you know were you can get those fuses at for a reasonable price? Thanks

 

How do you know that they were only functioning at low speed? Your description only notes that you "noticed this because water temps on my PFC were higher than usual." Did you actually check them at that time? And if so, how did you determine that they were only functioning on low speed?

The fuses are commonly available at all auto parts stores.

 

Yeah, I forgot to mention that I did pull over and noticed they were running on low, maybe could have been medium but definitly not high. My PFC is set to have the fans come on high at 87C and usually keeps it's temps down below 89C even on hot days. I noticed the temps went up to 96C and that was at night. I checked and the fans were on but running real slow compared to what I usually see.

 

Then I would check the relays and the wiring leading to them carefully. The PFC only activates the relays; the relays are the controlling component for fan speed.

 

Sounds like an open ground on the circuit to the #1 cooling fan relay.

 

Relays would probably be the easiest place to check first since they are all right there in front. What is actually the best way to test the relay? What makes you think it's Relay #1 and not any of the others?

 

Relay #1 is switched on by the A/C switch to increase fan speed. High fan speed requires that all 4 relays be closed. If you still get the other two speeds (low and medium), relays #2-4 are working.

You turned on the A/C and the cooling fan fuse blew, right? Sounds like a short to ground on the Y/W wire between the #1 relay and the fans. Or perhaps a short within one of the fans from that terminal.

 

Makes sense but it might be hard to check the path of the Y/W wire from relay 1 to the fans as most of it is taped up and runs underneath where I can't see it. But it sounds like a good place to start so later I'll get it up on jacks and check all the wires while I'm at it. Thanks for your help Kento and DigDug I appreciate it

 

There's actually a simple test. Just remove the connector from the #1 relay, and use a multimeter to test for continuity between the pin with the yellow/white wire and a nearby ground. If you get continuity, there's a short.

If you find that there is a short, disconnect both fan connectors, and perform the same test for continuity between the pin with the yellow/white wire and ground. If you get continuity here, the short is in the harness. Otherwise, it's in the fan itself (unlikely but possible).

 

That sounds like a pretty good idea. Only problem is I'm not quite to sure if that fuse blew right when I turned the AC or before that, but nonetheless I could test all the wires going from the relays to the fans and if I find any shorts to ground I could go from there. Thanks again

 

I'm thinking you should be able to see any problems with wiring close to the relays or fan motors, as that's where most of the problems like this occur. Check the wiring loom carefully where it contacts the fender well liner; a lot of people had shorts because of the tire wearing through the liner and then the wiring at full bottom. Check the wiring leading from the fan motors when you pull off the IC; sometimes the IC rubs against the wiring as the engine moves (the wires leading to the fan motors run along the fan mount assembly, making it easy for rubbing contact), eventually wearing through the covering.

 

Man I hope that is it cause if it's somewhere other than the relays or the wiring from them things might get expensive like a new fan motor.

 

If the fan motors are indeed functional as you state, then it's highly unlikely the problem is related to them. They either work or they don't; there's no grey area in-between.

If you do somehow end up replacing a fan motor, I would call Ray Crowe at Malloy Mazda. I don't know what his price is, but I recall obtaining a new motor for something like $170 dealer cost plus shipping a few years ago from a friend at a dealer, so it's can't be that bad.

 

I was kind of figuring the same as far as if it was the fan motor itself then they wouldn't come on at all. But I have been surprised by some things about these cars before.

 

I blew my fuse when one of my motor went bad. You can buy those fuse in pep boys or autozone.

 

There were probably other issues that resulted in your fuse blowing than the motor going out. I've run with one good fan motor for quite a few months before replacing it without blowing any fuses.

 

The only way I could see the fan itself causing the fuse to blow at a certain fan speed is if it had an internal short to ground on one of the power terminals.

 

Well after removing my ASP medium IC and the plastic duct for it I found at least 2 problems. Seems that the plastic duct rubs against the wires going into the fan motors. The fan on the driver side had the blue wire wore down to where copper was touching the fan motor and the fan on the passenger side had the black and green wires wore down to the copper and were touching each other. I temporarily put some electrical tape (all I had, no shrink tube) around the bare spots and put things back together.

Well seems fans will come on high now when I turn on the AC and do not blow any fuses, so thats good. However, my PFC used to kick them on high to keep the temps below 89C and now it seems they still don't come on high? Kinda confusing, maybe I'll post on the PFC forum and see if anyone else had something like this happen.

Thanks again for some of the advice guys, speeds up troubleshooting in my opinion. I'll post later on this problem I found as a warning to anyone with a SMIC and the duct that it could potentially wear through at some of those fan wires.

 

You're welcome.
It's one of those situations where examination of the parts to be installed helps avoid problems like this, but a new thread on the subject can't hurt.

 

I couldn't agree with you more, but it was KDR that installed that intercooler along with my single so maybe they didn't catch how it might wear away the insulation on those wires. No big deal as long as the motor is still good (which it should be) I'll eventually redo those connections.

Still would like to know why my fans won't automatically come on high like they used to at lower temps (like 87C or 88C). Wish I had that datalogic so I could see if they are still set to come on high speed at that temp.