1996 840 cruise control

What tests can I do to determine where my problem with the crusie
controls lie?

I follow the procedures laid out in the manual and do not get any sign
that I've been able to set the speed.

I.e., get up to 60mph/100KM, shift the switch to ON and then to SET and
hold it. WIth my old Ford, I get a throttle, kick to tell me that I've
succeeded.

I've also gone through the use of the up-throttle toggle and still have
not got a response.

I've checked the fuses and none are broken.

 

There are 2 common problems with cruise on the 850. One involves the
brake pedal switch, hook your foot under the pedal, and pull up on it
(the opposite direction to the way you normally push it) as you're
trying the cruise. If it now works, remove the kick panel and bend the
bracket so the switch is moved closer to the pedal's arm. The other
problem lives under the battery where the pump is. The cruise vacuum
pump is bolted to the bottom of the battery tray, and acid from the
battery can cause problems. If there's a problem in this area, it's
usually obvious (split or kinked hose, bare or disconnected wires etc.)
--
Mike F.
Thornhill (near Toronto), Ont.

Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

 

Mike F.
I have seen your name quite alot on this newsgroup and your info is
accurate! Do you work for Volvo/dealership??
G

 

No, but I've worked on my and my family's various Volvos for 25+ years
and have a friend with an independent Volvo specialist garage where I
occasionally hang out and learn a few things...

--
Mike F.
Thornhill (near Toronto), Ont.

Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

 

Mike F,

Can you tell me if the 1994 850 Turbo's cruise control vacuum pump is also
located under the battery? Cruise worked intermittently at certain speeds then
stopped and I suspect a vacuum leak in this system. Second question, do the
vacuum lines for CC run to the switch on the steering column?

Questions for next round relate to engine overheating at idle after warm-up.
Gauge fluctuates up to just below red zone but comes down once driving again.
Needle is accurate as AC heats up rapidly with needle movement. Car still
overheats with AC off. Radiator wad changed last week with no effect. Fan
works as advertised. Still need to check water pump though.

Sparky

 

Your cruise pump is indeed under the battery. The vacuum line goes only
to a vacuum switch on the brake pedal, (and clutch pedal, if equipped)
then to the actuator on the accelerator pedal.

If you're overheating at idle, and you're sure the rad and fan are OK,
then I wouldn't hesitate about looking a the water pump. If it's bad
enough to cause that problem, then you're living on borrowed time, and
if it fails completely, the timing belt stops timing and you have bent
valves and a very expensive repair bill.

--
Mike F.
Thornhill (near Toronto), Ont.

Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

 

Mike F,

I have looked over the entire cruise control system and cannot "see" anything
disconnected or damaged. Do you recall the line configuration on the pump under
the battery? I have one line going to the under-dash connection and another
fitting, black with small hole off the pump. Should this second fitting off the
pump be capped? Possibly the cap fell off? If my current condition were
correct, how would I test the pump for pressure/operation? I suspect the pump
but am not sure how to troubleshoot from here.

Sparky

 

Mike F,

I have looked over the entire cruise control system and cannot "see" anything
disconnected or damaged. Do you recall the line configuration on the pump under
the battery? I have one line going to the under-dash connection and another
fitting, black with small hole off the pump. Should this second fitting off the
pump be capped? Possibly the cap fell off? If my current condition were
correct, how would I test the pump for pressure/operation? I suspect the pump
but am not sure how to troubleshoot from here.

Sparky

 

Mike F,

I have looked over the entire cruise control system and cannot "see" anything
disconnected or damaged. Do you recall the line configuration on the pump under
the battery? I have one line going to the under-dash connection and another
fitting, black with small hole off the pump. Should this second fitting off the
pump be capped? Possibly the cap fell off? If my current condition were
correct, how would I test the pump for pressure/operation? I suspect the pump
but am not sure how to troubleshoot from here.

Sparky

 

Mike F,

I have looked over the entire cruise control system and cannot "see" anything
disconnected or damaged. Do you recall the line configuration on the pump under
the battery? I have one line going to the under-dash connection and another
fitting, black with small hole off the pump. Should this second fitting off the
pump be capped? Possibly the cap fell off? If my current condition were
correct, how would I test the pump for pressure/operation? I suspect the pump
but am not sure how to troubleshoot from here.

Sparky

 

Mike F,

I have looked over the entire cruise control system and cannot "see" anything
disconnected or damaged. Do you recall the line configuration on the pump under
the battery? I have one line going to the under-dash connection and another
fitting, black with small hole off the pump. Should this second fitting off the
pump be capped? Possibly the cap fell off? If my current condition were
correct, how would I test the pump for pressure/operation? I suspect the pump
but am not sure how to troubleshoot from here.

Sparky

 

The other line off the pump is just a vent, no connection needed. I
don't have a diagram handy, but the pump should pump vacuum throughout
the system. If you apply a vacuum to where the hose connects the pump
(even with the engine off), the actuator should start to open the
throttle. Pushing the brake (or clutch) pedal should dump this vacuum
and close the throttle. The only problem I've ever seen with 850 cruise
control other than vacuum was an electrical brake switch (the same on
that turns on the lights) that was out of adjustment. There is no
adjustment, to fix it I ended up bending the bracket it's mounted in to
bring it closer to the pedal.

--
Mike F.
Thornhill (near Toronto), Ont.

Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)