93 850 new fan installed, blowing cold, hack baffles?

[JimBee]

My new fan in the 93 works great, nice and quiet and can vary speed with workaround modulator.

Original fan was dead. Power stage was shorted to ground running fan continuously at full speed (so internal connected to hard ground).

The 4 thin wires to the power stage ware measuring 12 volts on the red wire input and low voltage at a couple of other inputs, so I assumed the ecc console controls were alive. But there are no leds blinking and the controls don't seem to be moving the baffles for heat/cold, or anything.

I also assumed that because the console controls were set to 72 degrees when things stopped working that the baffles would have stayed at those orientations.

But the fan is only blowing (ambient) cold, so at least one baffle must be set to outside air and the others aren't directing heat.

jreeds writeup here is detailed and helpful, in that he shows how to activate a baffle motor with a 9 volt battery. If I could do that from the plugs at the back of the ecc console unit, might that solve the problem without getting into major disassembly like he did, at least for now.
viewtopic.php?t=51078

I found a couple of schematics at this link, but I'm not getting a clear picture of how to use them (pp 159 -161)
https://www.volvo850.ru/shem/1994.pdf

While this seems like it should be doable, I'm over my head in the electronics so would appreciate some guidance. Afterthought: if I knew the color coding of the wires that plug into the motor(s), I could then activate them from the plug.

[jmartin919]

So 4/30 is the ECC, the dampers are 6/45-6/49, the B connector on the ECC has 16 pins. Depending on which damper you want to activate you put 12V across the M(otor) pins. Ex. 6/48 would be pin 4 and 5 on the B connector.

[JimBee]

Thanks, jmartin! If I'm getting only cold (presumably outside) air, I'm assuming the recirculating damper is open to ambient, so that needs to be closed (although the car door was open so air in the cabin was the same as ambient, but still if air was passing over the heater core and into the cabin, even with air in the cabin around 30F, air from the vents should have been at least warm, right?

Can you determine which is the recirculation motor from the diagram on p. 160?

It appears to be 6/48 on the right side of the HVAC duct near the ambient air intake. Your thoughts?

It all seems less mysterious, but am I going down the right path?

Also, most of the wire color abbreviations are obvious, but I'm not sure about the others.
I'm assuming: BN (brown) P (purple) R (red) W (white) Y (yellow) GN (green) BL (blue), but SB, what is that?

I'll take a closer look tomorrow.

[scot850]

Does your cold air flap operate at all? If you turn the A/C controls to re-circ, the flap above the fan should move.

You can see this 2 ways:

1) Remove the plastic shroud under the windshield over the windshield wiper motor. You will have to remove the 5 X T27 long screws holding the shroud down, remove the 2 drains by disconnecting them, and then removing the 2 wiper arms.

If you don't have a cabin filter you can see down to the cold air flap. If you do, remove the filter.

or

2) You can try and see if the arm moves on the servo motor for the cold air flap under the dash to the LHS of the fan motor. These can and do break. They are still available new at last check and relatively cheap.

If the plastic arm is broken, make sure you know where the servo motor is sitting when fitting a new arm.

Neil.

[jmartin919]

6/48 would be my guess as well. SB is black (Sable)

[JimBee]

Thanks, guys.
I removed the (filthy) cabin filter and I can see that the flap/door is down and the fan wheel is plainly visible. I was able to reach into that space and gently tried to lift the flap/door. It seems firmly connected and didn't move. I didn't force it. From the inside, I tried to move the plastic arm, that doesn't move, so I assume that means the linkage isn't broken.

Key on, I tried changing the recirc and ac rocker switches, nothing's moving. Likewise turning the knobs for heat range, nothing.

I previously measured inputs to the power stage on the 4 thin wires yesterday and got 12 volts on the thin red wire, I think 5 volts on another one in that plug, not sure about the other two.

So, seems like I'm back to trying to move the recirc/ambient air flap/door by electrically juicing its motor from the source plug behind the ecc console. Of course, it occurs to me there could be other dampers in there that will likewise need to be nudged—assuming the motors are working.

My next step will be try to juice the circuit with a 9volt battery if I can find the IDEAL testing tool, like this:
https://www.microcenter.com/product/448 ... -connector
Just strip off 1/2" and plug 'em in!