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Cool Fan 1 issues

6K views 17 replies 3 participants last post by  DrivenDaily 
#1 ·
10 LTZ been having issues with the 28 mini relay, which is cool fan 1. Car temp reaches above the temp half mark, frequently. Times I need to pull off and wiggle the 28 relay, or even sometimes leave it half way connected for it to work, most of the time it doesn't turn on, relay is clicking when it's being wiggled or taken out. So I know the relay works, also I have tried multiple relays.
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Only the high fan seems to be constantly working. I took apart the fuse box and found some burnt connectors. Do I need to hit the junk yard & snip a cooling fan wire, soldier it to a new connector?
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#2 ·
Poor connection generates heat causing expansion in the connector. Connector loses it's ''spring'' tension and just gets worse over time. Easy enough to replace the terminal in the fuse box. Needle to release locking tab and they pull out the back.
I'm not sure on which style terminals they use as they are a industry standard style.
JY box and just splicing in what you need is a OK option. 2x on soldier and shrink wrap the joint to insulate it.
 
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#4 ·
You will need to trim wire back until it's not heat discolored to get to ''fresh'' wire. May have to splice in extra wire to reach back into the fuse block but that's the idea.
Finding correct terminal end is key.
If JY box is cheap enough that's a option also.
 
#7 · (Edited by Moderator)
...where do I start?! 10 Malibu, 3.6. First, the tan female harness under the fuse box had 2 burnt terminals, which were fan 1 & 2. Went to the junk yard, found another housing (tan box) @ the junkyard & had the dealership de-pin & transfer the wires into the new box, being the terminals & plastic were melted & terminals would not fit properly. I figured being the terminals were burnt & the plastic was melted it wasn't getting good connection. After dealer soldered new terminals & re-pined my fuse box they tell me my fuse box was no good & has a short. I purchase a new fuse box, put that on & still NO fan 1. Turns out the dealership put the fan 1 terminal on the wrong location, electrical mechanic figured that out for me. Now, the electrical mechanic tells me my ECM is bad, says it's not sending signal to fan 1. WTH!! Fan 2 works, kicks on with ac. I've checked for continuity, relays are getting 12v, of course the fuse box is new & just for giggles I've checked the relays & fuses with a test light & a multimeter, all are good. Fan works when I tested it to the battery. The only means of having the fan run, is a wire ran from fan 2 relay to fan 1 relay. HELP!!
 
#8 ·
I'd ask the guy who said that the ECM is shot to show the outputs from ECM to both fans.

The ECM controls 2 of the 3 relays with one wire, the Serial/Parallel relay and the Fan 2 relay. It controls the 3rd relay for Fan 1 with another wire. Being able to see the output of that wire at the ECM with Fan 1 relay disconnected would let you know if it's sending a proper ground or not.

In short, the ECM will engage Fan 1 relay first. If it is powered, then Fan 1 and Fan 2 will both turn at Low Speed.

When the ECM gets a signal from the AC, it will energize the other 2 relays, allowing them to run at High Speed.

If the car is not overheating in city traffic, and the fans are running at Low Speed, then Fan 1 relay is being energized by the ECM. Case closed.

Double-check that he's telling you that the ECM is not controlling Fan 1, but means Fan 2.

If it controls Fan 1 but not Fan 2, you can force the Serial/Parallel and Fan 2 relays to energize, but you'd have to do the wiring yourself, since those other guys probably don't wanna touch that with a 10-foot pole.

I can guide you on how to do it without cutting any wires, too! It'll mean that whenever the fans turn on, they will always be in High Speed, but that's better than not turning on.

Reversing the modification will be as simple as unplugging some wires and putting the relays back in place.
 
#9 ·
So he says he tested the ECM & ground is not sending signal to fan 1. ECM is not controlling fan 1.

My fan 2 works. I don't have any issues with that. When in traffic it does go above the halfway mark, then fan 2 ONLY kicks on.

At the moment I do have a wire running from fan 2 relay to fan 1 relay, as you said. Being fan 2 is the only fan getting signal. With that being said, new ECM??
 
#10 ·
If you trust the guy, and he trusts his diagnosis, have him stand behind it. If the replaces the ECM and it still doesn't control Fan 1, then you don't pay, since what you're paying for is to correct the issue, not throw parts at it.

The ECM could have something as simple as a bad pin, a cold solder joint, or a bad foil trace on the circuit board. It's not impossible that it could be fixed, but there's no telling without looking. If he can't warranty his work for an attempted repair on the ECM, then his best bet is to replace the part and warranty his work that way.

If the ECM is at fault and you are not gonna be the one tearing into it, then your choices are to have him fix it, or replace it.

Since it's not sending the signal, it sounds like it needs to be replaced. Hopefully you won't find out that the poor workmanship done earlier is what caused it to fail!
 
#12 ·
I actually Googled the business, they had decent reviews. 5 stars from a number of people But, I don't know him personally to trust him much ya know. I ask as many questions as I can, & explain what I know so I don't get taken advantage of & look like a fool.

I have replaced the hood in the past, it has a small gap & I have noticed when I drive it through the car wash, the check engine light comes on & low engine power as well. Maybe I messed it up myself doing that? I'm pretty sure it's not the workmanship because the fan hadn't been working before I took it to the dealership. I've been having this issue for a good 2 years or so. I would usually have to pull off the road & wiggle the relays & at times they were really really hot to the touch.

What's your take on it boss??
 
#13 ·
The original failure of the fuse box may still be causing issues, or it could just be that it took out the ECM. I can theorize only so far, though.
 
#14 ·
I called the mechanic & tired to set up a date when he can fix it etc. I guess he was fed up with me from asking so many questions & trying to get solid answers..lol. Heck, I'm not trying to put $ into parts for my health, so skip that guy. I'm really not trying to run this wire from relay to relay too long. I'm stuck man..lol.
 
#15 ·
Depending on which terminals you've hooked up, it could be that there is no issue with how it's wired. If you know or can find out, share that and I can probably provide some useful info.
 
#17 ·
This is what it looked like previously, which is why I had the dealership de-pin & put on the new plastic piece that I found @ the junkyard. I guess the tech put the wire/terminal in a spot that didn't connect to anything. I figured this would solve the issue, being fresh wire & new terminals & better connection on the new housing. When the electrical mechanic opened it up, is when he noticed it was pinned in a blank location.

The second photo, is what he recommended I do, for the mean time. The second photo is also the brand new fuse box I installed, cause the dealer tech said it had a short. It only had a "short" because the wire was not in the right spot.
 

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#18 ·
OK, that'll do for a little while, but don't go a long time on it. It looks like that wire is the 12V power from the Ser/Par relay (Relay 29) to Fan 1 (Relay 28), which means that the single 30A fuse on Fan 2 (Relay 30) is covering both fans. Not good!

One way, which is pretty easy, is to buy an extra relay, and then use the same principle as that jumper wire, only you'd be wiring to that new relay. You can get 20A, 30A, and 40A relays at most auto parts stores and online, usually for $5-$10 each.

The Coil
The terminal where that wire is plugged into the set of 5 holes in the shape of a C is what we want to go to the coil on the new relay (85 or 86, it doesn't matter), then wire a small ground wire to the other coil terminal (85 or 86, whichever is left over).

NO (Normally Open)
The terminal at the other end of your jumper wire goes to terminal 87.

COM (Common, or Wiper)
Get a fuse holder with a 30A fuse and wire it from the battery to terminal 30. (Tip: Take the fuse out while wiring so you don't run the risk of shorting it out.)

NC (Normally Closed)
If your new relay has a terminal labeled "87a", do not use it. Just leave it blank.

Description

With that wiring layout, Fan 2 simply tells the new relay to turn on, and power to Fan 1 goes through that 30A fuse, through the relay contacts, and out to Fan 1. In essence, Fan 2 takes the place of the ECM telling Fan 1 to turn on, with no real load added to the circuit.

Just make sure that all connections are tight! That much current flowing on a poor connection will heat up and cause similar damage to what you had.

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