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Blower motor fuse keeps popping

Mbeas96

Mbeas96

Member
Joined
Aug 7, 2017
Location
Charleston
90 740, just finished heater core and now I'm tasked with getting the blower to turn on. It stopped worked over the last couple months of no use, before quitting it had a rubbing/whining noise that I assume meant it was on the way out.

Fuse 16 (I think, one fuse that was marked heater fan) keeps blowing (30amp) within seconds of trying to turn the motor on. Went thru 2 additional ones after I pulled the original blown one.

Am I right in thinking the motor is probably just seized aND a replacement will fix my problem? Or is it possible the resistor or other wiring could be fubar causing it to pop?
 
Maybe if it's fully seized. I've run with blowers that were too worn out to turn and never blew a fuse. They would still turn when rotated by hand, but not freely the way a healthy bearing would. But if you did a heater core change, there's a possibility you pinched a wire somewhere.
Also look for water in the blower housing. The FAQ says this can be a problem with 7/900s. Take it out of the plastic housing, carefully pry off the bottom plate and bang the motor against something. Try to get it so that you can at least spin it by hand a little, and tap the plate back on. If it still blows the fuse, it's the wiring or the resistor. But I've only ever seen resistors fail open. That would be a bad resistor to lose, too. $200 for that little piece of crap.
Fuse 16 itself is also known to cause problems. Read https://www.volvoclub.org.uk/faq/ElectricalCircuitsRelays.html#Relay_and_Fuse_Panel_Removal and then inspect your fuse panel, too.
 
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Well...that's not what I was hoping to hear. Ha. I'll probably end up removing the motor this week at some point. Hoping it's not a pinched wire, I would not enjoy going back thru all the trim pieces a second time. I also just went and checked out the 16 fuse holder and it looks good. No corrosion or melting.

If it is the resistor I'll end up getting one from a junkyard and honestly id rather do that than mess with the blower motor. From the searching I've done, apparently you have to cut the stock harness to wire on the new fan? Or does the one fcp sells connect to the factory harness? I believe it's the Four Seasons brand. If not, Id probably be just fine with a fan from Napa.

Trying to have heat on my 1000 mile round trip to Tennessee in 9 days..
 
Also to note (I should've mentioned before) the blower motor did not work before I changed the heater core. And the fuse was most likely already blown before I started messing with it this afternoon.
 
Mbeas96 said:
Well...that's not what I was hoping to hear. Ha. I'll probably end up removing the motor this week at some point. Hoping it's not a pinched wire, I would not enjoy going back thru all the trim pieces a second time. I also just went and checked out the 16 fuse holder and it looks good. No corrosion or melting.

If it is the resistor I'll end up getting one from a junkyard and honestly id rather do that than mess with the blower motor. From the searching I've done, apparently you have to cut the stock harness to wire on the new fan? Or does the one fcp sells connect to the factory harness? I believe it's the Four Seasons brand. If not, Id probably be just fine with a fan from Napa.

Trying to have heat on my 1000 mile round trip to Tennessee in 9 days..
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You don't have to cut the stock connector if you use an aftermarket blower. I'm using a VDO PM131, which is a blower for a full size Chevy, and have it connected to the stock harness using two 16ga wires with yellow female disconnect terminals on each end. If the blower you get only has exposed wire ends, you can just crimp on male disconnects. The FCP one might come with an adapter. But if not, do it how I said instead of mutilating the wiring harness. You'll feel better about it.
 
Now that I've seen pictures of the harness it seems easy peasy. I'll grab the same fan you mentioned from the parts store otw home tomorrow and see if I can't swap it out before it gets dark. Is it necessary to remove the fuel ecu/cage to remove it?
 
Mbeas96 said:
Now that I've seen pictures of the harness it seems easy peasy. I'll grab the same fan you mentioned from the parts store otw home tomorrow and see if I can't swap it out before it gets dark. Is it necessary to remove the fuel ecu/cage to remove it?
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Yes, remove both. I always disconnect the battery before removing the ECU connector just to be safe. Press down the clip, and firmly but carefully swing out the top of the connector. It was easier for me to remove the bolts holding the ECU to the bracket before removing the connector.
 
Sweet, shouldn't take too long and hopefully the other fan is a goner. Thanks for your tips and help! Very much appreciated!
 
Glad to help. Just keep in mind the VDO blower isn't quite as strong or durable as the Delco blower the car comes with. That thing is really worth the high price tag. But the VDO blower will work fine even if the heat isn't eyeball melting like the stock blower. Also, duct tape around the opening for the connector to seal off any gaps. That will help a bit.
This is for the model with AC, right? The PM131 won't work with non-AC models. They use a different 1-wire connector where the negative side connects to the chassis ground. A Four Seasons 35334 will work for the non-AC car. And if you have the AC car and feel like paying extra for one with an adapter, get a VDO PM3787 instead of the PM131. It looks like a 131 with an adapter. That might be the same as what you're seeing on FCP.
 
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It is the ac model. And I'm sure I'll be okay with the vdo, Its gotta be better than nothing...I'll grab one otw home today and hopefully post some pics of a very corroded fan motor
 
Ima start with saying, if anyone knows how to resize images thru the TB attachment, feel free to let me know...please.

So I grabbed a VDO pm131 from auto zone. Comes with 2 year warrenty amd I actually got to go behind the counter and find it...lol misplaced stock and bad employees.

Removed the old fan this morning. Super easy, took all of 10 minutes to remove and find it is completely seized. I couldn't spin it by hand at first. After some force it broke loose, but sounded rough. Amd yeah, all the leaves and pinestraw in the photo came from the fan

20191122_121824.jpg

<iframe width="560" height="315" src="https://www.youtube.com/embed/AleNoeYz2uc" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

And to my suprise, the new connector fits the stock harness and it locks in. So even easier!

20191122_122505.jpg

20191122_122406.jpg

Reinstalling was just as easy as removal and all in all probably only had 30 minutes into this. It blows great. Now to cover the hole for the wires with some tape and it should be set.
 
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It fit? Wow. I'll try removing the adapter wires from mine and plugging it in directly. The way it turns in the video is how mine behaved after they failed. Too bad the Delco blower is so hard to get apart. I wanted to try to fix mine with some new brushes.
 
It definitely doesn't "fill" the plastic portion on the stock plug, but the pins are correctly spaced and the lock clip fits great over the volvo connector. So it stays nice and tight. And for only 32.99 with a 2 year warrenty.
 
Mbeas96 said:
It definitely doesn't "fill" the plastic portion on the stock plug, but the pins are correctly spaced and the lock clip fits great over the volvo connector. So it stays nice and tight. And for only 32.99 with a 2 year warrenty.
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Yeah, less than half the cost of the Volvo-specific part. Oh, did the plastic cover on your blower have a small hole drilled in the bottom? I've read about these things becoming seized when water pools in them up to the motor. Mine has one already. But if yours doesn't, it just looks like a 3mm hole that could be made with a drill on low speed.
 
No hole was drilled in the fan cover, Its probably a good idea to though, right? To drain any water that may collect in there?

He's a pic of the back of the fan with the cover off, definitely a goner.

20191123_153444.jpg

I might pull the cowl off and see if there's any sealing I could do to prevent water getting in there...and pull any more leaves out
 
Yeah, but just a tiny hole right at the base of the cover. Maybe on the protrusion below the motor spindle, since it's the lowest point. I've seen a suggestion to buy some kind of filter that fits over the cowl air port without modification. I'll let you know if I find out what the filter was. Is that dirt on the bottom of the motor from the leaves composting in the housing?
 
I'll look forward to it, about the dirt, I assume so? It was hard chunks, more like dirt clumps...I kept the fan in hopes to also rebuild eventually. If possible.
 
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