Where is my Cruise Control Module?

[Uffeeh]

So, my cruise on my Sierra k2500 1997 doesnt work.
I've gotten tips about checking out the stalk by disconnecting the harness from the cruise control module.
Problem is, I cannot find it!

Please, could someone point me in the right direction? I would be much obliged

Picture from underneath my dashboard, is it visible?

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[1low95GMC]

Kitchen it is under the Hood on the driver side fire wall

 

[mattillac]

From what I have read, there is no cruise control module on a 97ish diesel. In the gas vehicles, the cruise control module will have a cable which pulls on a throttle etc, the diesel seems a bit different, the PCM will control the cruising speed(fuel delivery)on a diesel so there is no need for a separate module on the firewall.

The diesel PCM seems be located behind the glove compartment in the diagrams I have seen and that is where the book says to test from.

Not sure if the OP has a diesel or a gas truck, but thought I would mention the difference with the cruise controls just in case.

Please correct me if I am wrong because I don't have a diesel or a 1997.

Best of luck.

Edit: Looks like a diesel according to this post here:http://www.gmt400.com/forum/showthr...r-from-Sweden!&p=297764&viewfull=1#post297764

Check behind the Glove box for the PCM or start testing at the column connectors.

 

[Uffeeh]

From what I have read, there is no cruise control module on a 97ish diesel. In the gas vehicles, the cruise control module will have a cable which pulls on a throttle etc, the diesel seems a bit different, the PCM will control the cruising speed(fuel delivery)on a diesel so there is no need for a separate module on the firewall.

The diesel PCM seems be located behind the glove compartment in the diagrams I have seen and that is where the book says to test from.

Not sure if the OP has a diesel or a gas truck, but thought I would mention the difference with the cruise controls just in case.

Please correct me if I am wrong because I don't have a diesel or a 1997.

Best of luck.

Edit: Looks like a diesel according to this post here:http://www.gmt400.com/forum/showthr...r-from-Sweden!&p=297764&viewfull=1#post297764

Check behind the Glove box for the PCM or start testing at the column connectors.

Sorry, I forgot to mention it is a diesel that we're talking about.

Thank you very much for the information. Now i understand why i didnt find my ccm.

I will check the pcm to start with!

But this should mean that there only can be a problem with either the PCM or the stalk itself, Am i correct in thinking this?

 

[mattillac]

........But this should mean that there only can be a problem with either the PCM or the stalk itself, Am i correct in thinking this?

......after looking at a diagram it seems like the PCM controls the cruise for the most part and it gets +12v inputs from the stop lamp circuit/switch etc.............

.....Fuses appear to be: Brake 10A(hot in run), Stop/Haz 20A(hot all the time), Cruise 10A(hot in run).

Looks as if the "Brake" fuse supplies power to the PCM(stop lamp/clutch switch input), that power would be cut from the PCM whenever the brake pedal or clutch pedal are activated. Maybe brown wire into the stop lamp switch/purple coming out. Purple wire into the clutch switch/brown&white coming out. If power isn't passing through those switches as it should when the pedals are at rest then the cruise wouldn't work.

The "Stop/Haz" fuse seems to supply power to the PCM(stop lamp switch input)when the brake pedal is pressed, besides powering the brake lights etc. Maybe orange wire into the stop lamp switch/white coming out. Shouldn't be the issue though, your brake lights work.

The "Cruise" fuse looks like it powers the cruise control switch, when the switch is activated, power is sent from the switch to the PCM(ON input),momentary power is also sent from the switch to the PCM on separate wires for the resume/accel and set/coast functions..........

I would check the fuse(s)if you haven't already and then maybe test the brake light switch and the clutch pedal switch(if equipped).

The PCM will disable the cruise when either the clutch and/or brake are depressed, so the pedal switches are very relevant components, besides the three fuses and stalk/control switch. The vehicle speed sensor is also involved according to the diagram but I wont speculate on whether or not that could be an issue, I would guess that if the speed sensor was malfunctioning, that situation would trigger a check engine light among other things.

Here is a diagram(seems to be the right one). http://autolib.diakom.ru/CAR/GMC/1997/Suburban%20K2500/SYSTEM%20WIRING%20DIAGRAMS/16771.pdf

 

[outalne94z71]

when the pmd is going bad the cruise tends not to work, you should always have a spare pmd as they are common to go out at any time, the gray stanadyne one is your best bet, all other brands are flight systems units rebadged to whatever name and are prone to runaway conditions when they start to fail, you really should stay away from them.

 

[Uffeeh]

Thank you both for your help!

I have been reading everywhere here and on Dieselplace to find an answer.
I actually found that wire diagram but i cant find the right kables at the bottom of my steering column. EG. i dont seem to have a brown kable ground in the harness that connects to the stalk so i cant properly test my stalk.

Right now I'm thinking of buying a new PMD to have as spare. And a stalk, if i can find one used to try with.

My PMD looks pretty good, it sits by the ABS unit and on a heatsink and the engine is running very good.
But you never know.

 

[mattillac]

.....I actually found that wire diagram but i cant find the right kables at the bottom of my steering column. EG. i dont seem to have a brown kable ground in the harness that connects to the stalk so i cant properly test my stalk......

From what I can tell, you should normally only be testing for (+)positive battery at the cruise stalk/connectors, the diagrams don't show any ground wires going there.

The column connector(C266)diagram shows the following pins/positions are use for the cruise: A12, A13, A14 & A15.

The online diagram shows these colors at the column connector C266:

cruise on input-------------grey( A12 (black--------
cruise fuse---------------brown( A13 (brown-------
set coast input--------dark blue( A14 (black--------
Resume accel input---grey black( A15 (black--------

The diagram I have shows different colors(same pin locations though):

cruise on input-------------grey( A12 (grey------------
cruise fuse-----------------pink( A13 (brown----------
set coast input--------dark blue( A14 (dark blue--------
Resume accel input---grey/black( A15 (grey/black------

The diagram I have shows the power feed wire could be pink instead of brown(on one side of the connectors), but still located at pin A13 in connector C266.

Once you find the power to the stalk at pin A13, then you should be able to pull the cruise fuse(key in run position)to verify you found the right pin/wire.

The (+)positive battery power is only supplied to pin A13/cruise stalk when the key is in the run position.

Best of luck!

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http://www.justanswer.com/chevy/1mg51-1998-chevrolet-pickup-when-turn-headlights-switch-on.html

 

[Uffeeh]

Thank you mattillac!!!

That was extremely helpful.

I checked with multimeter on these cables. And the stalk is functioning on all the cruise buttons.
You saved me some work of changing stalks and purchasing something i do not need.

This leads med towards the pmd. Because i believe the brakeswitch is working properly. There is only one brakeswitch right? (I have a automatic).

I really apreciate your help!

 

[mattillac]

......There is only one brakeswitch right? (I have a automatic)......

There is only one brake light switch from what I can tell, but it has two poles/ciruits, so there are two circuits being switched at the brake pedal. One of those circuits is switched closed when the pedal is depressed and the other circuit is switched open when the pedal is depressed.

The brake lights work so I would assume the brake light circuit is being switched close when you depress the pedal, but the other circuit in that switch(unit)is suppose to pass power though when the pedal is not depressed, so the PCM is suppose to be getting power from that switch when the pedal is at rest which then enables the cruise to operate.

The brake switch should be checked IMO, just because the unit is passing(brake light)power when the pedal is pressed does not mean that the other circuit is passing power through when the pedal is at rest. These are two separate circuits with separate fuses and functions, they just go through the same switching unit.

At the brake switch: Maybe brown wire into the stop lamp switch/purple coming out. The power should be passing through that switch when the pedal is at rest, If you find those wires you should be able to verify that you found the correct circuit by removing the fuse labeled "brake", remember that circuit is powered only when the key is in the run position(not to be confused with the "stop/haz" fuse).

You are welcome, remember though I don't know what PMD even means, just trying to help where/when I can.

Good luck.

Edit: The orange wire into the stop lamp switch/white wire coming out should be for the stop lamp circuit and we assume that is working because the brake light operate normally.