cruise control

[Guest ekvh]

I get a 673 history code on my 88. When I attempt to set the cruise, it comes on for a second and then goes to the resume light. If I hold the "set" button in for a while, it sends a message that the cruise has been disengaged. I have checked the obvious in the FSM. It has no juice at the E and C terminals of the servo connection. The FSM goes on to tests for the servo and BCM. Couldn't there be other reasons for this occur such as malfunctioning brake switch. I replaced the vacuum lines and sprayed the lines going into the firewall as best I could. No apparent vacuum leaks. Any other obvious things that might cause this? I read in some previous posts that the wires going into the steering column can get bent and break, but haven't torn into that yet.

[Guest Drake]

Had the same problem with my 89. Drove me crazy (not too hard to do). One night on the way home, tried to engage the cruise. As I pushed the cruise control switch to the on position, the little amber led lit up nice & bright. As I released the pressure on the switch, I noticed the amber led wasn't as bright as the ones that were lit for the headlights & park lights. I then held the cruise button in with my finger and set the cruise button on the turn signal stalk. What a surprise, the cruise stayed engaged. I then drove through a slight dip in the road, cruise disengaged.

Contacts for the switch were dirty.

Over the weekend, I removed the headlight switch, removed the cover and button caps. I then sprayed all of the contacts with electronics cleaner and blew it out with canned air. Worked like a charm. I just wish I'd found the problem before purchasing a new vacuum release switch and a rebuilt cruise control module. Oh well. Hope this helps.

As others on this Forum have said, "Look for the obvious, don't just throw parts at the problem". I'll definately remember NEXT TIME.

Just read your other post about your electrical problem. My advise, correct that first, then look into the cruise problem. You might be putting the cart before the horse as they say.

[Guest Bobby Valines]

Drake, my 89 cruis does not work. I know my head light switch is dirty. Did you clean just the head light switch and your cruis cane on, or did you clean the cruis switch too. Thank you.

[Guest Drake]

My problem ended up being dirty contacts in the cruise control on/off button in the headlight switch assembly. I did not try to clean the Set button on the turn signal stalk. The cruise control engaged immediately when I activated the set button. I suppose you could spray electronics cleaner in the end of the stalk for good measure.

[Guest ekvh]

I was optimistic after reading Drakes remedy because my cruise button light under the headlight switches is dim. But I had no luck there. Mine still engages for a fraction of a second and then disengages. If I hold the set button or resume button on for long, it throws a code b673. I suppose I will have to figure how to pull the switch and stalk out and dissemble them and clean. Actually seeing the brake vacuum hoses is difficult, but I'll look there next. I hope it's not the BCM. Thanks for all the advice anyways. I need my cruise soon. I hate to spend money, but this is an item that will cost me money in the end as I will get a ticket sooner or later.

[89REATTAJIM]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ekvh</div><div class="ubbcode-body"> I hate to spend money, but this is an item that will cost me money in the end as I will get a ticket sooner or later. </div></div>

In the meantime, set your overspeed alarm.. Jim

[DAVES89]

The cruise control system we have on our cars is probably the most common in the industry. On my '89 when I disconnected my electrical power to the cruise sewrvo I had a printed warning come up on my touch screen.It also thru a code.

If it is not the small vaccum lines [as a matter of fact my lines looked new from the outside but were junk]it will be the servo.Those are the 2 most common problem areas on the cruise control.

[Guest ekvh]

Can the servo be worked on? Taken part and cleaned, I mean?

[DAVES89]

You can buy them in a u-pull lot for less then $10.00 all day long

[Guest ekvh]

Drake, To the best of my knowledge using the FSM my problem is somewhere in the 402 ckt. I think that means wiring. My message from the crt is "Cruise control disengaged" I am wondering if your dirty contacts problem is the same. Do you recall if the cruise light on the IPC would light up briefly and then switch to the resume light?

[Ronnie]

Don't overlook the obvious. What normally causes the "Cruise Control Disengaged" message to come display? Tapping the brake pedal. I would check the switch on the brake pedal and the wiring going to it for problems. If the contacts in the switch are dirty and vibrations causes them to lose continuity it would drop out the cruise and display the "Cruise Control Disengaged" message.

BTW, I couldn't find a 402 circuit in the wiring diagram of the cruise control in the FSM.

[Guest Drake]

ekvh, I would engage the cruise button, then push the button on the turn signal stalk. The cruise light would light on the IPC for a split second, then go out. When I tried the second time, it did the same thing, then I got the message on the CRT "Cruise Control Disengaged". The resume light never came on.