98 S90 vacuum reservoir location Topic is solved

[S90ken]

My 1998 Volvo S90 AC is cutting out under acceleration and/ or going uphill. Resumes afterwards. I found that one check valve on firewall was bad and replaced with a brand new OEM part. Also replaced several rubber vacuum connector lines on firewall around the two check valves that looked suspect. I now suspect the bellows under dash or perhaps more likely the vacuum reservoir. Can someone tell me where the reservoir is? Any other ideas? Thx.

[lummert]

It appears to be under the front of the car. Search: 1997 Volvo 960 a/c problem

[93Regina]

It appears

Nothing inside vehicle except vacuum pots to redirect air flow...here's how its setup on firewall

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[93Regina]

My 1998 Volvo S90 AC is cutting out under acceleration

I have no idea how electronics are setup....cutting out means what?

If yours has a MAP sensor, ECU may be programmed to cut-off AC under low vacuum "pressure" (WOT type conditions)

[S90ken]

1) I had looked under that volvo 960 post earlier and looked under my s90 for reservoir. No luck. I will look again. 2) thanks for the firewall diagram. That is where i assumed problem was originally. Replaced one of the check valves that i found was bad and a couple of the vacuum lines that appeared deteriorated. 3) cutting out means that under acceleration the air flow from vents in car either greatly diminish or disappears altogether depending on how hard the acceleration is. Actually it also does this even if the AC is NOT on and controls are set just to blow regular air. Have had car a long time. This is a new phenomenon.

[S90ken]

Topic NOT solved. Hit that button by accident.

[93Regina]

...looked under my s90 for reservoir. No luck

Years ago, in many vehicles, a mechanical slider (or rotary) switch controlled a vacuum switch to activate various "vacuum bellows" for redirecting air flow (vacuum bellows: 10, 20, 21, 21).

Newer vehicles, I don't know. Diagram shows (2) servomotor and a (13) solenoid valve. One might control hot water, and the other might be an electronic vacuum switch.

On my 1993-940, they used a vacuum controlled switch to vary amount of hot water flowing...vacuum pot was located in engine compartment, and hooked inline with a rubber hose. This vacuum pot needs to be changed...mine leaked anti-freeze.

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[S90ken]

Thanks folks. Problem IS solved now. Turns out when I replaced one of the check valves ( vacuum pots) on firewall I had split end of one of the new hoses I put on. AC great now even under acceleration! Will run you out of car. Tha ks!