Hey I have a 1985 volvo 245 with the m46 transmission. I am trying to figure out two problems with the car. one is that the temperature gauge has been going up with engine rpms and now is pegged at the top when the car is on. second pretty much as soon as this thing with the temperature happened my A/C stopped blowing cold air. the clutch is still engaging and disengaging but the air does not seem cool if anything it seems warmer. I tried to disconnect the sensor for the gauge and test it like the Bentley manual says but the gauge stayed up. any ideas on these problems thank you. the A/C was also charged and some wiring was fixed in the last month by a volvo repair shop. thank you any ideas are appreciated.



Edit- also I just thought about it and the A/C used to make the car change Idle and now it doesn't seem to do so it makes a different sound than. before and the idle doesn't change. just incase that's an important detail

 

Is the temp gauge now pegged at the top limit with the engine off. If you disconnect the wire on the temp sender does the gauge still stay at max. Does the gauge go to 0 with the key off. As for the AC it sounds like it is low on charge. Did it work well when it was serviced and if so how long after did it start to blow warm air.

 

"some wiring was fixed"... oh boy. yeah, 1985 is an 'ecojunk wiring' year, all wire in that car is suspect and prone to having its insulation flake off with age. these bad years are about 1983 to mid year 1987. late 87 cars are fine.

once the harnesses start to fail, often inside the black sleeves where you can't see the individual wires, all bets are off... Mercedes had the same problem 10 years later (93-97 or so), but most of those mercedes still on the road got new harnesses from the dealer in the early 2000s.

 

oh fun peirce sounds like a great time figuring this one out and to the other reply yes it goes down when I have the car off and second when I have the wire to the sensor unplugged it will still stay at the top. thank you for the responses.

 

one thing that would do that (peg the gauge even if disconnected) is if the wire is shorted to ground anywhere between the engine and hte instrument panel

 

Yep , that's my thought too.

 

yeah I hate to do it but I just don't have time to go through my whole wiring harness trying to figure out what's wrong with both these things. I ended up dropping it off at a shop they said both problems seem to be in the harness and they are going to take it apart and try to figure out where the wires are burnt or grounding. thank you all

 

sadly, if thats the original harness on a 85, odds are, if they cut back the outer black plastic sheathing, the whole harness will be a crumbling mess, the more its touched, the more will fail.

that said, Dave Barton sells custom made replacement harnesses, I believe your car takes this one,
https://www.240turbo.com/volvoharnes..._240_non-turbo

I note they are on back order at the moment but claim just a few weeks lead time. Barton is totally legit.

 

yeah I guess i just gotta wait and see what they can do. it's hard because i need to have A/C and I really need a temp gauge in atlanta. so hopefully they fix it if not yeah idk. we will see

 

At $370 for the harness I assume you are gonna see maybe 8 hours of labor on top of that. This isn't going to be a low cost fix.

 

if you have patience and can follow directions, harnesses are fairly easy to replace, they just take time. lay out the new harness on top of the old before unplugging anything, and swap it one piece at a time. I'd probably start at the ECU under the passenger side dashboard, as the old one has to come out of the firewall before you can feed the new one through

 

ok peirce just wanted to update you. they said the car is ready I picked it up and seems to work great they just replaced all the wires that were mangled causing the problems. hopefully nothing else happens for a while. they were talking about how they used to replace harnesses but Volvo stopped making them and they are just always out of stock or on backorder. thank you for the help with my issue. peirce and jagtoes

 

Barton is getting those harnesses from a supplier in the Netherlands. if it says 'out of stock', it means its one he regularly stocks, and he really does expect more in the indicated time frame.

 

yeah but it's working good for now and I might have to resort to buying one if it happens again. thanks

 

Somehow I think you are at the beginning of the end of the wiring. Good luck.

 

I was thinking should I try and get rid of this car before something else more expensive happens. I'm really not sure. thank you just trying to see what you think since you know all about the wiring on these cars.