Automotive Business Talk

Happy Traveler · Guest

(Cross-posted to both AAF and AMFE usenet groups)

The CC on my '98 Expy (V8, AWD, Limited) failed after almost 100K of
faithful service. Followed the self-test procedure in the workshop manual
and didn't get very far. Not even trouble codes being flashed. Checked
wiring, fuses, clock spring contacts; all fine. Well, it's a bad servo, I
thought. So bad that it can't even diagnose itself. After being cruise-less
for a couple months, I purchased a new one. Installed it, pushed the buttons
in the specified sequence, you guessed it: the same result as with the old
one. Well, there was one significant difference -- took the vehicle for a
spin, and the with the new servo the CC is working just fine.

Perhaps I am doing something wrong, but it seems that the test procedure for
the fancier body style, the one with the tiny cruise control buttons on one
side of the steering wheel and radio/climate control buttons on the other
might be different. Anyone aware of tech note or something to this effect?
It will probably apply also to the fancier Crown Vic/Grand Marquis and
others of similar vintage. Would be nice to have it if the thing ever fails
again. And it may prevent others from throwing away a good CC servo (which
ain't cheap) when the problem is actually elsewhere.

For completeness, the procedure in the book goes something like:
1) Hold the OFF button while turning ignition to RUN. Release the OFF button
2) Push ON within 5 seconds of step 1
3) Push ACC, COAST, RESUME (I am writing this from memory, the order at this
step may be different)
Each of those button pushes is supposed to be acknowledged by a blink of the
CC light. After the last one is pushed, the light should blink once for
'pass' or provide a trouble code, if any. A dynamic response would then
follow, with the servo pulling the cable about 10mm.

As I mentioned, in my case the story ends with a single flash after step 2,
then nothing. This is with both a defective and a brand new servo that works
just fine.