Cruise Control Problems

[KZCool]

Iv'e had my AT 99 outback sport for a year now and when I first got it I had to jiggle the cruise control set lever to get it to set.  After a while it would just shut itself off and not come back on.  Increasingly it didn't want to come on, and now wont come on at all. I've checked the vacuum hose and its fine, taken the lever out and took it apart to clean the contact points, replaced the main CC switch, and checked to make sure the plastic plunger of the break switch was still there and all the parts are fine.  I'll be checking the continuity of the actuator and break switch tomorrow but i would really like some input as to if anyone has dealt with this before.  I have a 1,700 mile trip this thursday and CC would make it soooo much better!

[lmdew]

Well, you got most common items covered.  

 

Clock Spring? 

 

Any problems with blinkers, horn, airbag?  Those are all part of the clock spring wiring.

[Fairtax4me]

Did you check the continuity of the select switch contacts?

Did you check the diodes in the select switch?

 

There is a black plug (either 5 or 6 pin) with only 3 wires under the steering column. This has the wires for the cruise select switch. Wires are the same color as those at the switch. Check for voltage on those while you move the switch. The switch shares power with the horn relay so should have battery voltage present at all times.

 

There is a switch on the clutch pedal also, be sure to check that.

[ivans imports]

+1 clockspring

[KZCool]

I checked the horn and all that as I drove (felt like an idiot blaring the horn down the highway) and it is all good.  I'll have to check the wiring under the steering column for continuity. How do I check the diodes and where are they?

[Fairtax4me]

Diodes are in the select switch on the back of the cicruit board.

Easy to check with a multimeter when the switch is apart. The diodes only affect the cancel setting though. So not quite as important.

 

You don't have to pull it all apart to check them though. The switch is easy to check for continuity with an ohmmeter.

 

The green/black wire at the switch is common.

Yellow/Black is the Acc/Resume signal

White/red is the Set/coast signal.

 

Unplug the switch.

With an ohmmeter touch the red lead to the green wire, black lead to the yellow wire. Should have 0 ohms if you push the switch to Set. If you pull the switch to cancel you should see close to 7 Mega ohm resistance. This means the set/coast side diode is good.

Should see the same readings for the white wire by moving the switch to Acc.

 

If you don't want to take the steering wheel apart you can check this under the column at the black connector.

The wooe colors will be as follows:

Green/Red is common

Black/White is set/coast signal

Tan is Acc/Res signal

 

If you don't get the proper readings at the connector under the column it could mean the clockspring is bad. Retest at the switch connector in the wheel.

[KZCool]

thanks a lot.  I'll check that now.

[KZCool]

I did a couple different things.  Checked the voltages, going in was fine but it was below 10 coming out, and checked the ohms.  The switch itself had .3 ohms about, and after the clock spring 1.7 to 2.3 ohms. I wouldn't think that would be a big issue though.

[Fairtax4me]

Yeah that seems fine.

The voltage on the outgoing side will be affected by how much resistance is in the cruise module. If there were 0 resistance it would activate the horn relay and make the horn sound.

 

Next I would make sure you're getting 12v to the cruise module (the pump) and the signal from the switch is making it there. You might want to find an FSM for the car with wire diagrams to help with that.