1994 850 HVAC Question

Post by **scot850** » 28 Oct 2021, 19:11

That would tend to say to me that either the cabin sensor for the passenger side is still blocked or has failed, or there is a problem with the ECC control unit which at the age of your car is not impossible. There have been members that have disassembled the units and replaced some of the components that seem to be regular failures as these unit age.

Neil.

rsmigel · Post by **rsmigel** » 29 Oct 2021, 05:18

The passenger side temp fan behind the grab handle appears fine as the fan blades spin-up at ignition startup just like the little driver’s side fan. And there’s no error code being stored… yet.

I’ll check the code readout again this weekend.

I’m leaning towards picking up another ECC dash unit from eBay as they’re selling for $80-150 these days.

Post by **abscate** » 29 Oct 2021, 05:27

Don’t feed the junkyard hyena grifters

Climate modules at pnp are $10-12, offer $25-30 on eBay

Do some research on volvowebstore to find the compatible years

FRAM · Post by **FRAM** » 29 Oct 2021, 17:30

I have been slowly pulling various HVAC parts for my 97 850 as I troubleshoot issues.

My vote is the ECC is at fault here. I just went through this on the way to work on Wednesday. The fan is usually on low and then it went full blast and full hot. Nothing would change the heat or the fan speed. The lights would not even come on with REC or AC off. Thankfully I had 3 more ECCs in my trunk from the weekend when I pulled some. So I pulled over and switch out the ECC for a spare and the heater functions that did work before started working again.

I am concerned with the vintage of our cars finding ECC that still work will become much more difficult. I do not get the impression these are 40 year strong electronics especially with what a hot box our dashes become in these 850s. I suspect this heat also kills the plastic in the dashes too. I have split sockets on flaps and broken flaps in my HVAC system I need to repair next...

rsmigel · Post by **rsmigel** » 30 Oct 2021, 06:05

FRAM wrote: ↑29 Oct 2021, 17:30 The fan is usually on low and then it went full blast and full hot. Nothing would change the heat or the fan speed. The lights would not even come on with REC or AC off.

That’s exactly what initiated this thread…

Post by **scot850** » 30 Oct 2021, 15:21

If I recall the early 850's had a different ECC unit to the 95-97, but I may be wrong. I am fairly sure I have an 850 ECC (it will have C rather than F temp increments). I have no need for it. It came from a wrecked car but was working before the accident.

I am sure that if you post the part number (there is usually a label on the case) there may be someone here who may have a spare unit lying on a shelf.

Neil.

rsmigel · Post by **rsmigel** » 30 Oct 2021, 15:34

Good idea. I’ll try to pull the ECC tomorrow.

rsmigel · Post by **rsmigel** » 31 Oct 2021, 13:17

Still no ECC error codes thrown up. Unit has green plugs, P/N 9144256-W411K.

Anyone have a spare ECC for sale? Or I have a 40K mile used turbo from a totaled ‘95 850 for trade.

Post by **abscate** » 01 Nov 2021, 04:26

Used from 93-97 850s. Don’t forget to ask junkyard pickers here and Also put an ISO In classifieds

Post by **RickHaleParker** » 01 Nov 2021, 05:34

scot850 wrote: ↑30 Oct 2021, 15:21 If I recall the early 850's had a different ECC unit to the 95-97, but I may be wrong.

You are not wrong. The later ones had a modification in the wiring harness. The early and later are not interchangeable.

1994 850 HVAC Question

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