1994 T. 300+
No blower fan this week. How do you tell if motor or resister.
Already checked fuse.
Nebraska winter requires a blower.
Thanks

If you remove the resistor and connect the power leads together the blower will run (even with the ignition off). I used a multimeter in 10amp mode for this purpose and with a brand new blower motor it ran at full speed.

If you find that the blower is still working but the resistor is bad it makes sense to replace both. An old blower motor will eventually kill the new resistor and you'll be back to square one.

I just went through this process a few weeks ago so it's fresh in my mind. Let me know if you need anything else.
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Zack 94' 850 Turbo Wagon (232k)

I agree, change both blower motor and resister with new parts. Even if the blower spins with a power source hooked up, it may still be faulty and be drawing too much current, causing the resistor to go bad. After replacing my motor twice and the resistor twice with used parts over the last year, I again had no heat for the last couple weeks. I decided to order new parts from fcpgroton and distalled them yesterday. I've never had the heat blow so well in the 7 years I've had the car. And no fault codes. $350 for both parts new. Volvo resistor, behr blower, no headaches, no frozen toes.

You have the ECC system, so check the codes for B-1. If the blower hasn't made any terrible noises lately, I suspect it is the resistor.

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My back feels better when I sit in a Volvo seat

replaced the resister today with a boneyard part. it works like a charm. thanks for your advice.

Well i have no way to check codes so I pulled a motor with no positive results. Left the old motor in place. I have now pulled out the resister and will get it at the bone yard ASAP. i've also read about a green relay and an ECC module. Where are theses located? I have the auto temp AC/Heater system. Thanks for all your posts.

Unless your OBD port is broken, you should be able to get codes from the B-1 port. If the resistor has been removed, then your codes will show that.

The ECC 'module' is the dash unit itself. Don't worry about the relay as I have yet to see a dead one.

The resistor for the manual climate control is different from the ECC, so when at the junk yard, make sure the module in the dash is the same as the one in your car.

The only reason to check the codes in B-1 is when the recirc and AC switch lights blink orange about 20 times at start up.
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My back feels better when I sit in a Volvo seat

Take the glove box out you will see a green relay (blower relay) pull it out and see if it's burned 25 bucks on eBay sometimes just pushing down will fix problem used resistor on eBay 20 bucks

For cars with manual climate control, if the fan doesn't work at speeds 1,2, and 3 but works on 4, most likely it's the resistor. You could also test the blower motor with a 12 volt source. If you touch wires to the blower where the wire harness connects and to your battery and it spins, then the motor is good. The resistor and the blower are close together so if you think it's one or the other, I'd try testing the blower and if it works, I'd try another resistor while you have the glove box and knee bolster out. Make sure you hold on the the blower motor firmly if you are going to test it so it doesn't spin out of your hand and break the fan cage if it does turn on.

On 850's up to 1995, you can get fault codes for climate control from the B1 port on the OBD1 diagnostic helper under the hood. Hopefully, the little wire that has the probe which you insert into the different ports to get codes isn't broken. I have 2 850's and both cars have worn wires where the probe wire meets the OBD1 unit itself. Be careful to not tug the probe too hard (from the OBD1 cover which stores the probe or the different ports). The wire is short and you may tug the wire from the unit if the diagnostic probe pops out with force.

Also the resistor for cars with auto climate control are different from those with manual climate control. So if you're gonna get a resistor from the wreckers/scrapyard, make sure you pull it from a car with the same system as yours.

Hope it's not the control panel itself that is faulty. They were $1200 from the dealer and the part has been discontinued (at least in Canada).

You should find the wiring diagram for your year car. Its a 205 PAGE PDF file.
Use a search engine.

There's schematics for all the sub systems including the heater fan
(Pg 183 in my 95 850.). Also each subsection schematic has a parts location
diagram so you can find stuff.

You'll want to get a volt meter on the different parts of the circuit to see what quit.

There's stuff like the ignition switch, relay 2/30 "105",
fuses: 11/5 & 11/31, etc etc.

After checking both fuses
I'd start at the motor to see if the voltage is there and the bearings seized up maybe, and work back.

Bill