Cruise/ speed control

[francis tibbetts]

With a 94 Explorer the cruise has always been intermittent over the 30k miles
I've owned the truck. Sometimes it wont come on, but keep trying and after
a while (sometimes minutes, sometimes hours) it comes back. Other times
it just drops out when it's been running fine. The only specific is that it
quite often (but not always) drops out when turn signals are applied, as in a lane change. Does any one have any suggestions? Thanks, F.T.

 

[ricco750]

Check your Dump valve, here's a link:

http://www.explorerforum.com/forums/showthread.php?t=221094&highlight=dump+valve

 

[MrShorty]

The only specific is that it quite often (but not always) drops out when turn signals are applied, as in a lane change.

It's been too long, so I don't remember the specifics very well, but it seems that my BII did the same thing. I don't remember specifics, but it seems that it had to do with the hazard light wiring or brake light (which goes through the multifunction switch along with the turn signals). Some wiring fault was causing the "standby" signal to get sent to the cruise control whenever I signaled.

Do you have a wiring diagram? 1st thing I'd probably do would be to get a wiring diagram (libraries often have good manuals with good wiring diagrams, if you can't find one on the internet).

 

[Roadrunner777]

The control unit senses the lead to the center brake light. If the voltage goes high (brake light on) it sends the speed control back to idle. Here is the tricky part: When the brake light is off, it looks for the lead to be near zero volts. It uses the center brake light bulb as a path to ground. If the bulb is burned out, then the lead is floating, it is neither at 12V or ground potential. If you have a digital voltmeter, and it is not connected to anything, it will show floating voltage, same idea. The brake light must be good to bring the lead back to ground potential and that makes the control unit happy.

 

[mehedgec]

I'm in the same boat as you. Was intermittent, now nothing. I spent an hour or so today messing with stuff, and still no luck. Gonna go to the junk yard next week and get a speed control amplifier and give that a shot. I'll post here if it works for me.

 

[johnvosh]

I'm also in the same boat as the rest of you. It was working when I first got it and now nothing. Checked all my bulbs and they are all good. Checked all vacuum lines and they all look good as well. I was trying to check out the dump valve by pressing the brake pedal to see if I heard a clicking sound. I didn't get anything. Does this mean that the dump valve is possibly bad?

 

[Roadrunner777]

The dump valve will not make a click. The body of the valve is on an adjustable barrel. You should be able to feel up the brake pedal for it. If you feel something about 1" diameter that feels like threads, that's it. Pull down on it with a wiggling motion and you will adjust it down (making a clicking noise as you adjust it.) My problem with this now is that it will not stay adjusted down, so I adjust it, and I guess using the brake pushes it back up. I'm replacing gauge lights in a few weeks, maybe I can get a good look at it and fix it permanently.

 

[johnvosh]

Got my cruise fixed today. Grabbed the speed control module from in the glove box of a '91 Explorer and it seemed to have fixed my problem. We shall see how long it will last!

 

[mehedgec]

I went by the junkyard today and got a speed control amplifier for like $3, put it on in the parking lot. Got up to speed and hit the cruise button, aaaaand jackpot. I have cruise control again as well.

Pull the glove box down and its mounted with a bracket behind the latch. 2 bolts and it comes right out, just gotta remove the 2 wiring harnesses.

 

[runderwo]

Could someone with a NON cruise equipped 93 or 94 do me a favor and look behind the glovebox and see if those 2 connectors are stashed back there? It seems that there was two different dash wiring harnesses for 91-92 for with cruise and without, and I am wondering if it is the same deal on the 93-94. I definitely do not have those plugs on my non cruise 91 (and wish I did..)