1998 S90 blower replace when replacing blower resistor?

jefflamonica · Post by **jefflamonica** » 23 Mar 2016, 16:51

Lummert, where can I get a look at the right diagrams, and hopefully, pinouts and target resistances?

93Regina · Post by **93Regina** » 23 Mar 2016, 20:11

jefflamonica wrote:MCC system...a manual system...

It appears Volvo had two different MCC setups, and the 850 is twitched differently than your S90

I don't have the part number index for this wiring diagram. This is a 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???

Tell me, does this look like your setup?

My note: 1994-940, pg 165

: Capture.PNG (32.18 KiB) Viewed 1656 times

lummert · Post by **lummert** » 23 Mar 2016, 21:00

93Regina wrote:
jefflamonica wrote:MCC system...a manual system...
It appears Volvo had two different MCC setups, and the 850 is twitched differently than your S90

I don't have the part number index for this wiring diagram. This is a 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???

Tell me, does this look like your setup?

My note: 1994-940, pg 165

Capture.PNG

The resistor unit on my 1988 760 Turbo Wagon doesn't look like this one. I had assumed that 88-90 760, 91 940SE, 92- 960 , and S/V90 all used the same ECC.

93Regina · Post by **93Regina** » 23 Mar 2016, 22:06

lummert wrote:The resistor unit on my 1988 760 Turbo Wagon doesn't look like this one...

I think his setup is same as 1994-940, and the Resistor Pack can be tested via placing one probe where arrow points, and then touch the other points on ohm scale. Of course, on the work bench

: Capture.PNG (215.75 KiB) Viewed 1632 times

jefflamonica · Post by **jefflamonica** » 24 Mar 2016, 08:08

This is what my resistor looks like: http://www.ebay.com/itm/260854741647?eu ... 32197&cp=1. Very different than so many I see. I'd have to pull the glove box to recheck, but I believe I had 2 wires going in on one plug and 3 on the other.

jefflamonica · Post by **jefflamonica** » 24 Mar 2016, 08:33

Thanks, 93Reg and Lummert. Reg, that last diagram might be very helpful. So, not being an electronics guy, let me see if I understand the test procedure. On the resistor module, probe on pin where red/white wire would connect. Other probe incrementally on yellow/red (4), white/brown (2), white/black (3), and yellow/white (1), I should see the resistance decrease each time I move from one pin to the next? (I sure hope this corresponds to my wiring colors.)

If that's the case, what's the next step in the logic? Resistor tests okay means control unit is likely the culprit? And the red/white wire going to the resistor should only be energized in fan switch position 5, right?

From what I've read, there's a relay soldered on the PCB of the control unit -- possibly acting as the max fan relay we've previously discussed. Not sure, but if stuck in the closed position, could be the cause. I've also read a lot about cracks in solder on those boards. With your help, I'm getting an education here. I appreciate it.

Please check my thinking above, and tell me if I'm on the right track.

jefflamonica · Post by **jefflamonica** » 24 Mar 2016, 09:48

93Reg -- I had a chance to look closely at the green book diagrams you sent. My wiring colors are definitely going to be different than the previous diagram. Here's what mine should look like. I just wish I could see the connections inside the components, like on your other diagram, so I could figure out which wire does what.

: resistor wiring diagram.jpg (43.91 KiB) Viewed 1560 times

I'm not a veteran at reading these things. I'm guessing the 4/40 B and C are the plugs going into the blower resistor from the control unit. Sorry for being a newbie at this.

And here's the component location with wiring colors

: resistor component location.jpg (80.9 KiB) Viewed 1560 times

It would be nice to have the list of all the code numbers in the diagrams so I know what I'm looking at.

jefflamonica · Post by **jefflamonica** » 24 Mar 2016, 10:03

Comparing the diagram you sent with the arrow on it to this green book diagram, I may have decoded this.

- Your arrow (red/white) corresponds to connector A blue/black above, and is fan speed 5
- On connector B in the green book diagram...
- Orange is fan speed 4
- Blue/red is fan speed 3
- White is fan speed 2
- VO (violet/orange?) is fan speed 1

Resistances across connector B points should be lesser with speed 4 and greater with speed 1, right? What is a bad test going to look like?

93Regina · Post by **93Regina** » 24 Mar 2016, 11:25

Duplicate Post

93Regina · Post by **93Regina** » 24 Mar 2016, 11:36

jefflamonica wrote:It would be nice to have the list of all the code numbers in the diagrams

I'm winging it here since I have never seen these setups before. What threw me was the "4/40" code, which is connoted as "A/C Controls, MCC." Seeing multiple 4/40 units was suggesting multiple parts, in my mind; and then seeing "ECC" nomenclature there, was also a curve ball, but I suspect there is sometype of ECC-motor-control device used, maybe on ductwork or something (I haven't checked other sources to confirm).

In this 1994_940_wiring_diagram, on PDF page 175, there is a listing of codes, and I assume Volvo standardized these code numbers.

1998 S90 blower replace when replacing blower resistor?

Re: 1998 S90 blower replace when replacing blower resistor?