1996 Volvo 960 Air Conditioning Problems Topic is solved

[93Regina]

my car started hissing from the right side when I hit the re-circulation button.

Hissing noise would suggest a vacuum leak or a vacuum pot is shot. Simple, start removing that "stuff" in front of passenger's feet, until you find the source.

[Scottyv]

But to continue the saga of searching down Ecc vacuum blend doors issue with a 1997 960 v90.

I found like others here the best place to start is to test the vacuum lines, testing from the outer fire wall. near the Ac accumulator.

this is the process I used.
1. locate the three vacuum lines going into the car through the fire wall.
2. The one to the heater control get disconnected from the three.
3. Then the two with the little black and white values get separated. by carefully pulling off the little sections.
4. The plug up one of the two lines.
5.Then hook up a vacuum suction pump to the other unplugged line. (I used my brake bleeder vacuum pump with a little connection to get good suction.
6. Pump up the vacuum suction to 10 psi and see if it hold suction. if it does its a a good line and the interior system it runs is good also.
7. Test the second line. Test the second line by unplugging your plugged line and test it in the same way. if it holds pressure your problems is in the outside vacuum lines or suction accumulator under the car. (if the second line hold pressure the inside system is in good working order)
8 If the second line fails to hold pressure , that portion the interior system is failing, a line. or a 1997 Volvo "Vacuum Valve" (Blend Door) part number 9463040 valve , or one of the "blend door vacuum motors" has failed.
(all the interior parts are very hard to get to but possible.by removing much of the under dash components, there are many videos for this)

Solution 1:
Plug the bad line with a plug or reverse the little valve so air cannot be blown out of the system.
hook up the main line to just the good line, and don't for get the valve to allow air into the system but not out so the system will hold the blend doors in the position you direct them to from the control dial.

Remember if One line holds pressure up to 10 psi with out failing and one hose con not make suction, this is usually the blend door to the passenger side floor heat door.
Solution 2:
remover the dash and find the bad part or leaking hose.

what I did :
I reconnected the main vacuum line from the engine system to the one line that held pressure and plugged the other line by turning the value around so it could not leak out .

Result:
After starting the car and running the system I found the only blend door that did not work was the pass foot well.
seems that all other doors worked or worked well enough to get defrost, front vent and lower foot wells air when turning the knob.

I kept the bad line plugged and have had good air circulation since
I assume the passenger side lower blend door is the door motor that has failed is the one behind the glove box. one of the easiest to change out which I will eventually get too
hope this helps other as much as the previous posts helped me.

thanks

[Scottyv]

one more note on the 1997 960 vacuum system for the blend doors and the ECC.
I thought I would add this bit, the line that I plugged only operates the interior temp sensor in the dash near the windshield. see the link diagram the other line operates the blend doors, I thought it operated the pass side floor blend door but it seem it may not.

http://www.volvotips.com/index.php/940- ... ir-manual/