My cruise hasn't been working, but the horn did. Since I didn't think it was the clock spring I next checked the brake switch. The switch was showing open no matter what it's position. I figured since it was bad anyway I would open it to see what happened. There is a sliding contact with a piece of copper that touches the two terminals when the switch is pressed. One of the two contacts had broken off. Turns out that that copper piece is symmetrical and has a new pair on the other side. I turned it over and the switch seemed to work.

The switch is adjustable. I couldn't figure out why it was shorter when I put it back together. The shaft that clips on to the contacts has a little clip. The shaft has ridges that hold the contacts on. I pulled the clip out and reset it to the highest point. I then put the switch back in and marked with a sharpie where the shaft was with brakes in the normal position. I then removed the switch again and pressed it down until it adjusted to the sharpie mark. Re assembled and everything works!

The switch is closed with no brakes, and opens when you press the pedal. There could be some range of adjustment with the switch, but I just set it to the most sensitive, as soon as you touch the brakes it opens.

The switch is not meant to be opened. I used a knife to cut one of the little tabs, then pried it up all around. It was tough, but I was able to do it several times.

 

When I read the title of your post, I thought I'd be reading about "no overdrive, no CC", and we'd have to ask if you'd recently switched to LED brake lights -- but you surprised me.

 

Wow, good to hear you figured out the problem.

Just an FYI, the replacement AM part is only $10.99. It would save some aggrevation in prying apart the old one.

 

That is actually the brake light switch. The cruise control switch is green. It is about $20 on that site.

List: Search for 'cruise control release switch' | O'Reilly Auto Parts

 

The CC used to be released with the brake light switch. Do they use a separate switch now? It seems less reliable, and possibly dangerous. If the CC release switch fails, and you apply the brakes, slowing the car down will cause the CC to apply more gas to try to keep the speed up. This happened to one of our test cars at Ford when the brake light switch failed, and it almost caused accidents on a few occasions before we fixed it.

 

The cruise control for 1986-96 uses a vacuum servo; for 1997 only, it's an electronic servo instead (I posted more info on this here).

Only the 1997 version uses two separate switches on the brake pedal.

Click HERE for larger

 

Accidental double post deleted. Caused by ford-trucks.com database error message causing me to assume the first posting had not been updated to the database.

 

No CC today going to work. I printed out some diagrams, started checking when I got home.

Horn = OK
Brake lights = OK (important! CC will not engage with all brake lamps burnt out (or with old-school LED lamps installed))

I pulled the connector at the CC servo (remember: 1997 is unique among Aerostars in having the integrated electric CC servo). Checked for

Key OFF: pin 9 (brake switch for CC only) = ~12v (OK): brake CC switch OK
Key ON: pin 7 (power) = ~12v (OK)

Connected the ohmmeter to pins 5 (Command) & 6 (Command return). Then I put the ohmmeter on the windshield and exercised the switches.

The resistance check on the switches showed:

ON = 1.2 ohm (OK)
Coast = 120 ohms (OK)
Resume = 2200 ohms (OK)
Set = open (Bad. Supposed to be 680)

While holding down the Set button, I moved the steering wheel about 90° and the resistance comes into range. Move the wheel back to neutral and it goes open again: bad clock spring.

These things ain't cheap! There does not seem to be internet consensus on the correct part No. for 1997, but several eBay sellers and at least one Ford dealer online are claiming F5TZ-14A664-D will fit. None of the big chain auto parts stores list a clock spring for 1997 Aerostar at all.

[later edit]

Because ON/OFF/COAST/RESUME/SET "commands" (resistance levels) are sent through the clockspring via the same two wires, and because all tests of those resistance levels were OK except one, the problem cannot be the clockspring. I'll take the SET switch assy. out tonight and measure things there.

 

I found that I was able to set the CC by pressing ON, then COAST. The CC worked OK that way, but of course you could not ACCEL using the broken button.




(click on image for larger)


The FSM's EVTM for the cruise control steering wheel switches diagram has two errors: it is missing the horn button, and it had an extraneous S200 connection listed on circuit 248 line. I've corrected both via PhotoShop in the last diagram above.


To get at the steering wheel switches, first remove the airbag using 1/4" drive 10mm DEEP socket to remove the four nuts:




The airbag lifts out of the steering wheel. Disconnect the airbag connector. Airbag connectors automatically short when disconnected (on the airbag side) so a static charge cannot fire them once removed from the circuit. They're actually safer when removed than when connected.




Four screws retain the two black plastic switch pods to the steering wheel. The wiring between the switches is a bit fussy to remove, but only requires patience.




This is the bad SET switch, removed from the PCB:




Digging around, I have a scrap board with identical physical sized switches. Tactile switches come in various heights (I had to order a weird height one for my keyless remote unlock FOB last year), but these LCD monitor switches fit perfectly. I only changed the SET switch.




Replacement switch installed:



It works fine, but it doesn't "click" with as much authority as the original: it feels wimpy. I think I'll get a JY switch assy. and swap out either the assy. or one switch.

 

Speed Control Indicator Light



Aerostars didn't get a CC Indicator lamp (shows when CC is active), but the Ranger and other Fords of the era did. On the '97's CC, it can (should) be able to display diagnostic information too, as it does on other Fords.



If I had had a CC Indicator lamp, checking the switches would have been a snap: Step 3 would have not completed.

Perhaps if I ever get around to installing that Bronco instrument cluster and getting a tachometer, I'll find a way to connect the CC Indicator. Although the '95-96 Bronco also does not have a CC Indicator, perhaps I can use the Anti-Theft indicator for CC.

 

92-96/7 Bronco/F-series did not have an Anti-Theft light, nor a cruise light, sorry.

 

The Bronco cluster I have has a socket labelled "Anti-Theft". I believe I pulled it from a '94.

The picture I took in 2015 just barely shows the Anti-Theft lettering on the plastic overlay, at the lower right of the image. I'll try to take a better pic tonight.

I know PATS was fully implemented later (98?) but it appears they have the overlay labelled earlier.

 

F150, F250, F350, & Bronco Instrument Cluster comparison chart (by Steve83).

See No. 11 on the 1994-97 versions.

(click on image for larger)