'95 850 Cruise Control points of failure?

payote · Post by **payote** » 24 Feb 2009, 12:51

My cruise has not worked at all since last summer but as it was failing it would hold for a while and then disengage. Does this behaviour provide any clues as to whether is would be the brake switch, vacuum lines or the controller?

Post by **MadeInJapan** » 24 Feb 2009, 18:54

Yes, that's how our old 850's cruise control died- it was the vacuum hose attached to the cruise pump under the battery tray.

Craigd2599 · Post by **Craigd2599** » 25 Feb 2009, 06:12

I've talked to a couple Volvo guys and they said the elbow in the vacuum line under the tray always drys out and cracks.

Delboy3867 · Post by **Delboy3867** » 06 Mar 2009, 14:01

Same issue on '96 850. Cruise was working, started to act erratically, then stopped completely. Did without it for weeks then, on a whim, pulled up on the brake pedal, heard a small click, and it's worked fine since. From what I read, the brake switch seems to account for about half or more of cruise issues and it's cheap to try it out before getting hands dirty.

crisleggett · Post by **crisleggett** » 15 Apr 2009, 02:23

My cruise control has been acting up and then tonight it stopped while in use. The cruise light went off and I was unable to switch it on again. I immediately thought it was a fuse. When you refer to the brake switch what exactly are you talking about?

Post by **MadeInJapan** » 15 Apr 2009, 19:32

The brake switch is actually slightly above the brake pedal under the knee cover on the driver's side. The way the pedal arm is, when you push down on the brake pedal, it pushes in a plunger for the brake light switch....this in turn turns off the cruise control. Check to see that this plunger/switch is aligned correctly. If it's not, you could be driving around with the brake light on and cruise control disabled all the time.

Post by **marginal** » 03 Nov 2009, 13:56

I wonder what could be the problem with mine.
The symptoms are as follows:
1. When I activate it it takes about 1-2 seconds to start (which I believe is too long).
2. It does not control the speed evenly, often slowing down and then accelerating again.
3. Just a very light touch on the break pedal stops it (I'm not sure this is not OK though).
Could this be a leak in the vacuum system?
BTW I checked the the vacuum hose attached to the cruise pump under the battery tray, and it is OK.

Thanks for the help.

Post by **MadeInJapan** » 03 Nov 2009, 15:51

Sounds like a leak...check it carefully...all the way to the ends.

Post by **marginal** » 03 Nov 2009, 16:02

Thank you MadeInJapan.

Is there a drawing or a pic of the CC system?

Post by **MadeInJapan** » 03 Nov 2009, 16:18

Unfortunately the diagram in VADIS doesn't show the entire hose system, only what's up at the cruise control motor itself

That said, you might find information in the downloadable manual on the 850. I'm adding the section on the cruise control here:

cruise control system.pdf: (315.89 KiB) Downloaded 1164 times

'95 850 Cruise Control points of failure?

Re: '95 850 Cruise Control points of failure?