When I got the car it was working well, except it would occasionally drop out of holding a speed. Hitting the resume buttin again would fix it.
Now this seemed to occur when going over a bump or similar rough surface, so I adjusted the brake switch, it was adjusted to come on at the slightest movement of teh brake pedal. It made the problem worse, in fact, teh cruise wouldn;t work at all then.
So I adjusted it back and it's still dead.
I also removed the stock stereo and amplifier at around the same time, but my memory is that I played with the switch before I removed the stereo.
The pathetic Haynes manual ( I don;t know why I bought another Haynes manual, about as useful as toilet paper in a tornado) says "take it to a Volvo dealer".
Like cruise controls are some sort of black art.....
Anyone got any suggestions?

REgards, Andrew.

 

I hear ya on the Haynes, its ok for some stuff but...

This might work better for you,
http://www.brickboard.com/FAQ/700-900/CruiseControl.htm

The main directory is here, save it to fav's, you'll be using it.
http://www.brickboard.com/FAQ/700-900/FAQSummary1.htm

Cheers Gerard.

 

I have a 740T and mine does the same thing. I read somewhere that a bad vacumn line could be the culprit, and a line that runs underneath the battery tray, commonly gets eaten up by battery acid could be the culprit. I've not checked into it yet, but post your results if you get it fixed. Thanks

 

O.K, I had a good look under the stering column, just rechecking wiring.
There are two brake switches, one has the vacuum switch and an electrical switch, the other (I assume) is brake lights, firther forward. It is an electric only switch.
The front switch has a green wire with black plug on one side, and a two wire yellow with black plug on the other.
The rear switch has one wire in, one wire out One is yellow, forget the other colour. I traced the wires from the rear switch, andthe yellowwire terminated at about 8 inches as a piggyback spade connector. I thought this odd! As you know, a switch only turns current on and off, so there had to be power for that rear switch. I assumed the rear switch was teh cruise switch, as it had the vacuum line.
Anyway, plugged the piggyback connector onto teh front switch in place of the two yellow plug, put the two yellow plug onto teh piggyback spade, and there you go, cruise control!
Why was the piggyback connector off in teh first place? Well, when teh cruise was malfunctioning, I removed and reconnected all the plugs to ensure I did not have a bad conection, and it's possible I forgot to reconnect it. It is very easy to miss, in that it's a fairly short wire, and blends in with the two yellow wires on teh front switch.
However, the piggyback connector was not the tightest of fits either, and perhaps this is what caused the intermittent fault before I played with it.

Regards, Andrew.

 

I have the same problem on my '91 740 turb.. I have noticed that if i put my foot under the gas pedal and lift the pedal up towards me.. the cruise control stays on.. don't know why this works.. hope this adds to the solution