Volvo 850 ECC to MCC swap, anyone done it?

sheasin88 · Post by **sheasin88** » 26 Jan 2021, 09:54

Hey all, my 850s ECC has been a nightmare sense I got the car, its always blowing an actuator, internal flaps bind up, air only comes out of 2 vents permanently, you know the usual daily ECC problems lol. Well im sick of having to remove the dash once a year and I have a 850 parts car with a MCC, anyone on here ever swap the HVAC system in these ECC cars to MCC?
To me atleast this seems very possible as a bolt in swap, only extra step i can see from looking at wiring diagrams appears to be swapping the fan speed regulator and finding the pinout of the ECCs harness to splice in the the REC, AC, and fan speed switches.

Post by **erikv11** » 26 Jan 2021, 10:17

I haven't heard of it done but bottom line is I don't know.

The MCC uses completely different actuator systems - pulley and cable stuff. My guess is it would only be possible if you (a) swap the entire dash and (b) hack the electronics appropriately.

Post by **abscate** » 26 Jan 2021, 12:05

MCC is only manual in the temperature blend doors, air selection and recirc/fresh are electronic.

ECC is really reliable, why are you blowing things on this? Find the faults and fix them

FRAM · Post by **FRAM** » 29 Oct 2021, 13:08

I have a 1997 850 T5 which has a dash in rough shape. The ECC system needs the actuator on the driver's side fixed. When I pull this dash off I would like to put in a dash that is not so broken as mine. I've been practicing dash removal in the local wrecking yards.

I have come across some lower model 850s with clean dashes but they have the MCC climate control. Can I pull the dash and the pad for these and still fit my ECC Controls into the place the MCC was? Is there more work I should know about beyond swapping controls?

Post by **scot850** » 29 Oct 2021, 13:34

What is actually wrong with your own dash? Is it just the firewall mounts that are bad? You can repair them with some work, and I am about to do that yet again on my current car.

Without looking at wiring diagrams I am not sure if the MCC and ECC dashboards are the same. I think the top removable pad and passenger airbag will be the same and the operation of your CDM/Instrument cluster would be the same. The issues I would see would be in the wiring harnesses and if they are interchangeable and I wouldn't know that without pulling one and comparing.

I think it is highly unlikely Volvo would have designed a lower dash section that is not modular for ECC and MCC.

The heating system will use the same outlets I would suspect for air.

The possible differences may be the wiring loom on the dash. I would believe they could worst case be swapped over from the original to the 'new' one.

I had a 98 dash that I had pulled as the mounts were pristine, but the wiring harness was noticeably different to the 99- cars on the V/S70's. I dumped it when moving which I regret but I did not have the storage space when we moved.

I now have one from a 99 with minor cracks on the dash mounts. I will repair it using JB Weld plastic 2 part epoxy, my little butane powered plastic welder from Princess Auto and some thing metal strips I bend to shape to strengthen the mounts. They will get screwed and bonded to the mounts. Below are repairs to the last car I did this on. My buddy has had this car for over 3 years and 30,000+ km and it is still quiet and way stronger than new!

: Dash mount repair (1)

: Dash Mount repair (2)

: Crack weld repair

: Crack weld repair (1)

: Metal bracket forming

Good Luck!

Neil.

FRAM · Post by **FRAM** » 29 Oct 2021, 16:53

Nice work on the repairs. I saw one of Robert DIYs videos on repairing the mounts. I'm hoping a newer one won't be so bad.

scot850 wrote: ↑29 Oct 2021, 13:34 .... The possible differences may be the wiring loom on the dash. I would believe they could worst case be swapped over from the original to the 'new' one.

Thanks this is what I am wondering about. I'm late to the Volvo 850 game. I bought mine last Xmas and late at night I started pulling my dash pad to get to a broken cluster. I'm a old Jeep Cherokee guy so pulling out dashes and interiors is just another day of vehicle repairs for me. However in the Volvo's case it was dark and I had no idea how fragile and brittle the dash plastics were as I pulled out the cluster. I broke large chunks of the upper dash off and the pad is warped as a result. It drives me crazy. I'm told I'm lucky as my dash hardly makes a noise unlike most Volvo 850 dashes of this vintage.

If I am going to pull the whole dash to fix my heater flaps I thought I might as well fix the broken dash in the process. I have more than a couple of what looks mint MCC dashes in the right color to pull if I can swap in my ECC with the MCC dash. I would hope they are like you said. Perhaps the right connections are in the MCC dash as long as I pull what is needed from my current busted up dash?

FRAM · Post by **FRAM** » 10 Nov 2021, 15:51

Bump.

Anyone pull off swapping a MCC dash into a ECC dash and then retaining the ECC controls?

Post by **scot850** » 10 Nov 2021, 16:35

I think the likely chances someone has done this is fairly low. Not sure why someone would swap to MCC by choice.

While I believe it is un-likely Volvo made 2 different lower dash sections i don't know. The only way to figure this out would be to pull one and remove yours and compare. I will try and see if there is anything on Vida that may help to clarify, but it won't tell us is the physical plastic parts are interchangeable and swapping a wiring harness over is all that is needed.

Neil.

Post by **abscate** » 10 Nov 2021, 19:52

I’ve got p80s with both MCC and ECC

I can make some measurements if that will help.

FRAM · Post by **FRAM** » 11 Nov 2021, 20:11

Thanks! I've found a couple of MCC dashes in great shape. My dash needs to be replaced so I'm hoping to make this work :-/