1998 S90 blower replace when replacing blower resistor?

[93Regina]

Any guidance from here will be appreciated. .

Here's an ebay ad: HVAC Blower Motor Resistor WELLS JA1691 fits 95-98 Volvo 960 2.9L-L6

RE: "Mine is an MCC system"

Try ECC: PDF page 66: TP3913202 960 1996

To confirm ECC, try these instructions: 960 AC diagnostics

Again, there is a cheap fix via using PWM control switch.

[93Regina]

Stock Code 9134772 ; 6847567
Manufacturer Volvo
Categories
This product is no longer available.

Heater unit 960 e. C. C 1995-, S90, V90 960 1995-. S90, V90

Product Fitment/Applications
Volvo 960 1995, 1996, 1997
Volvo S90 1997, 1998
Volvo V90 1997, 1998

Cheaper at Amazon: Wells JA1691 HVAC Blower Motor Resistor

[jefflamonica]

Thanks, again, 93Reg. At this point, chasing the proverbial wild geese with this is getting old. Seriously considering the PWM approach. Thoughts on this 20 amp controller? http://www.ebay.com/itm/111930282177?_t ... EBIDX%3AIT

[93Regina]

Seriously considering the PWM approach.

If fuse #7, located by driver-door's dash, currently runs the fan-and the fan turns off when switch is in off position, I would insert a 10A-15A fuse there since PWM specs are: Input current: 10A,the max.20A I doubt if a good fan would draw 10A, but a bad fan could exceed that value.

That unit uses 25-kHz frequency, so I would not place it near an ECU.

Both ECC/MCC's resistors will get hot, and I rather suspect the ECC resistor can't take as much heat as wire-wound resistor (MCC), like when a fan-motor is failing. If previous owner post-phoned replacing the fan motor, when bearing noise/etc appeared, this will cause extra resistor heat when amperage increases.

Is your unit an ECC? Your wiring tends to suggest this is the case. I suspect code item 6/27 is your electronic fan switch control, which works with the ECC unit.

As noted above, if you can turn fan on/off, then you might use the hot wire at ECC plug for the PWM unit...but if fan runs all the time, then I would find HVAC's incoming power wire from fuse box, and splice into it somewhere.

[jefflamonica]

I'm tracking with you, 93Reg. Mine is MCC, based on the control knob configuration on the control unit. The fan runs all the time with the key on. Turns off when key is off. Thanks for the recommendation about not putting near the ECU. I'll find someplace to mount it safely. I have a question: not knowing what else in the system is powered by that #7 fuse, wouldn't it make sense to splice into the fan circuit on the output side of the fan control switch, so the variable power output of the new controller doesn't affect voltages going to something else in the system? The fan itself runs fine and doesn't make excessive noise.

[jefflamonica]

MCC system...a manual system...

68 MB file, so DL and SAVE.

On PDF page 23 (218), it shows MCC setup, and on PDF page 248 (219), it shows component location.

From a 1994-940 wiring diagram, they show these numbers below as this, which the last two seem not right
4/40 - A/C Controls, MCC
2/10 - ECC Power Unit...maybe it shouldn't be in drawing?
8/22 - Solenoids, ECC...screwed up drawing???

93Reg, I went back and looked at the component locations and wiring diagrams you sent above. This is weird. The wiring colors on the ECC seem to match the connectors at my blower resistor. Yet, the control unit in the center of the dash, seems to be an MCC unit. Mine looks like this, except there's a snowflake icon on the compressor on/off button:

960climatecontrol.jpg (13.86 KiB) Viewed 2352 times

Curiouser and curiouser...

[93Regina]

This is weird. The wiring colors on the ECC seem to match the connectors at my blower resistor. Yet, the control unit in the center of the dash, seems to be an MCC unit..

Apparently, someone had a copy of the Mickey-Mouse-Mechanic's FAQ

I'll have to study schematics later, but off-hand, I suspect fan was harded-wire somewhere.

[jefflamonica]

I wonder if the car was originally ECC and someone swapped the control unit for an MCC one. The wiring harness in the vehicle (wire colors, etc.) seems to follow the ECC diagram.

[93Regina]

I wonder if the car was originally ECC

Could you pull fuse #7 by driver's door, and see what happens to fan motor?

They both have a 6/27 fan switch, but electrically, they are different beasts. I've never seen either, but all that I can guess is power is being sent from somewhere to power up the blower motor.

Does the temp control work?

[jefflamonica]

I'll try to remember to pull the #7 fuse when I get home tonight. The temp control does work. The air vent controls work, for the most part. Mostly panel and floor. The bi-level and defrost are a little weak. Probably a vacuum line somewhere in there.

Regarding power being sent to the fan directly, I read on one of these forums that there is a relay soldered on the circuit board of the control unit. Not sure if that's the high-fan relay, but my S90 doesn't have one near the blower like earlier models. Providing that is true, is it logical to suspect that relay may be stuck closed?