Heater issue diagnostics

Xcountryer · Post by **Xcountryer** » 11 Dec 2010, 06:32

Greetings. I have a 98 v70 XC. Heat stopped working most of the time recently but after researching, I am more confused.

The heat will still work sometimes. I think when the temp outside is say > 30 FH.

Yesterday with temps in the 20s, I drove 1.5 hours and was frozen when I got to work.

I do smell a bit of sweet coolant briefly when starting the car, but no water where my feet are, or condensation.

I am unclear as to whether the button for the AC light should be on or off. I would think off but AC in Volvo terms might mean general air conditioning - i.e. hot or cold v. as we Americans think of AC hot wheather remedy.

How do I tell if it is the blower, the thermostat or something else ?

Frozen...thx

Post by **EstVolvo** » 11 Dec 2010, 07:56

Check the temperature gauge.
If it comes up fast and stays at 3 o'clock your thermostat is fine.
If it doesn't come up and goes down on highway - the thermostat is bad.
The A/C - Owners manual says two things
1. The air conditioning system functions only at temperatures above 32'F (0'C)
2. If the function selector is set on defrosting and the blower is set AUT the A/C system will be on at this time even if the AC OFF button is depressed.
So who knows what is going on ...

Post by **BEJinFbk** » 11 Dec 2010, 11:52

Step 1 - Is there an adequate level of coolant in the system?

Klausc · Post by **Klausc** » 11 Dec 2010, 13:05

I leave my AC switched on year round, never know when it is going to go above freezing in Minnesota

If your blower is on AUTO and the Vents on AUTO as they should be, do the AC/Recirc lights blink orange after startup? If they do, then there is a fault detected by the ECC.

If the blower does not come on, slide the blower switch to high speed. If nothing, then check the fuses.

Xcountryer · Post by **Xcountryer** » 11 Dec 2010, 14:01

Thx. Coolant a little low. Will fill.

Will also check fuse.

Yesterday in NY area did not get above 30. No heat no matter what combinations.

Just now, driving home, AC light was on, blower on auto and I was getting heat though it was not blasting out. Temp is 46 here today.

So, maybe it is blower fuse and low coolant. I will fix this stuff tonight and tomorrow and see if that is the issue.

T H X so much.

Post by **Ozark Lee** » 11 Dec 2010, 22:38

Let's back up a bit and get some more information.

Do you have an electronic climate unit or a manual climate unit?

They pretty much look the same but the electronic version has AUT setting and the temp settings are in actual degrees. The manual unit has fan speeds from 0 - 4 and no AUT markings.

To your specific problem, regardless of which climate unit you have, does the cabin blower come on at all?

As I type it is 14 degrees Fahrenheit here and falling fast so I feel your pain.

...Lee

Xcountryer · Post by **Xcountryer** » 12 Dec 2010, 11:45

Thx. It is the electroniuc version.

Coolant is filled. I checked the fuse and it is fine.

The cabin blower is not coming on at all.

Today, it was raining and 52 FH. I had condensation so I shut off all vents and directed to the windshield. Barely functional.

Any remedies to fix the blower ? Thx

Klausc · Post by **Klausc** » 12 Dec 2010, 12:02

Go here, it is a write up in the repair database:

https://www.matthewsvolvosite.com/forums ... =1&t=19322