91 Cruise Control Issue--Speed Sensor???

[KS-Ryan]

Below is the test procedure for the cruise control system. My question is based on the "driving" portion of the test. When I am driving and the cruise is in diagnostic mode the cruise light stays on solid and will go off whenever I hit the brakes. Is this a brake switch issue or a speed sensor issue?

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
A. Turn the ignition switch on.
B. Turn the control switch to SET/Coast position, and keep it there.
C.Push the main switch ON.
D.check that the indicator light "CRUISE" lights-up in the
combination meter.
E.Turn the SET/Coast switch off
F.Meet the conditions listed in the table below.
G. Read the diagnostic code on the cruise control indicator light.
.................................................. ................
#1 Turn the control switch to SET/Coast position
there should be two flashes and then a second break and then two
flashes, then break then two flashes etc. If you get the flashes your
SET/Coast circuit is normal.
#2 Turn the control switch to RES/ACC possition.
this time you get a pause and three flashes, repeated again and
again. if you get the three flashes RES/ACC circuit is ok.
#3 Each switch is turned on
a. Control switch to CANCEL.
b. Stop light switch, (step on brake)
c. parking brake switch. ( pull up parking brake)
d.Neutral start switch. ( put in neutral)
if when you test each of the 4 cancel switches you DO NOT get any
flashes then those switchs are normal.
THIS IS YOU, And now you have to leave the driveway.
#4 Two parts for speed sensor
A. Drive at 25mph or below. if there are NO flashes sensor is normal.
b. Drive at 25mph or over. you should get constant steady blinking.
if she blinks sensor is ok.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

 

[none]

Not sure about your issue, but where did you find that diagnostic procedure?

 

[CJF]

When I am driving and the cruise is in diagnostic mode the cruise light stays on solid and will go off whenever I hit the brakes.

That's probably normal as long as the light comes back on once you're off the brake; I'll try it on my rig later today if I get a chance.

In the meantime, if you're antsy go ahead and pull the speed sensor; you'll likely find it fouled with gear oil, in which case you've found your problem.

Cheers,

Curtis

 

[landcruisher]

same problem

That's probably normal as long as the light comes back on once you're off the brake; I'll try it on my rig later today if I get a chance.

In the meantime, if you're antsy go ahead and pull the speed sensor; you'll likely find it fouled with gear oil, in which case you've found your problem.

Cheers,

Curtis

i dont have blinking light above 25mph other than that everything is normal even speed sensor is clean not a single drop of oil on it .Is it still the speed sensor or actuator? is there a procedure to check actuator?

 

[danimal24]

Same here. I think its the speed sensor...

 

[CJF]

speed sensor is clean not a single drop of oil on it

Clean outside or clean inside? Pull it and take a look if you haven't.

The test is pretty conclusive. I ain't giving you your money back if I'm wrong, but no blinking light = no signal from speed sensor circuit.

 

[danakittilsen]

My diagnostic returns two flashes for the set circuit and three for the accelerate circuit, but no flashes when I test the cancel circuit. So my question is: cancel circuit, where do I start looking for problems?

1991 VX limited HDJ81 (stock so far) w/ winter package & drawer/bed.

 

[CJF]

My diagnostic returns two flashes for the set circuit and three for the accelerate circuit, but no flashes when I test the cancel circuit.

if when you test each of the 4 cancel switches you DO NOT get any
flashes then those switchs are normal.

 

[landcruisher]

did pulled sensor apart and no oil inside no oil outside and same no blinkin light after 25 mph after claening

 

[landcruisher]

can anyone tell me where to buy this speed sensor?

 

[CJF]

....

 

[CJF]

One caveat:

The test procedure in the first post is from the FSM for a US spec. 91-92.

I would think the procedure for other years/markets is very similar if not identical, but I certainly couldn't guarantee that.

 

[CJF]

did pulled sensor apart and no oil inside no oil outside and same no blinkin light after 25 mph after claening

Just remembered the FSM also has a multimeter bench test for the sensor, for extra verification.

 

[danakittilsen]

Fair enough, I guess I didn't explain my problem in this thread (I have in another). My cruise control may work occasionally, but will invariably shut itself off after not to long.

As to my first post on this thread..I miss-read the diagnostics procedure.

 

[Michael Hanson]

Test actuator. Mike

 

[Calellis]

Hi guys,

All tests for the indicator stalk tested normal. I am not getting a cruise light at all below or over 25mph.

Fair to assume the sensor is the issue here?

 

[CJF]

When exactly DOES your cruise light illuminate?

 

[Calellis]

It works as expected apart from the actuator setting any speed.

ie: Cruise button clicked > Green light holds steady on the cluster.

The diagnostic mode shows the correct feedback when testing the set/acc and res/coast up and down stalk, it also flashes off when using foot brake, hand brake, neutral gear or cancel on stalk.

When I drive in normal mode the actuator won't take over the drive and set a speed at all.

When driving in diagnostic mode the green Cruise light is not on at all.

Does that help any feedback to assist?

 

[CJF]

Failed speed sensor would usually be Cruise light ON when starting the test drive, and then staying illuminated (rather than flashing) when driving over 25mph.

Definitely worth pulling the sensor and bench testing it; that's the most common failure point on a 91-92.