Instructions and helpful information.

The Cruise Control on a GM product does not have its own fuse.  It is usually covered by
the IGN fuse or the GAGES fuse in the fuse box.  Thus, if the complaint is more than just
the cruise control, check the fuses.  If the complaint is only the Cruise Control, this unit
will help you trouble shoot the wiring and tell you whether it is the multi-function switch,
the brake switch, the clutch switch (on manual transmission models) or the electronic
cruise module.  This unit will diagnose the multi-function switch used on GM products
from 1984 on.  It will also diagnose the wiring to the electronic cruise control module.  It
will NOT be helpful on the vacuum cruise units such as appeared on 1984 Fiero beyond
the multi-function switch.

Check out the multi-function switch as follows:

Look under the dash and locate the connector identical to the one on the end of the
CRUISE CHECK.
Pull the cable from under the dash, plug the cable into the CRUISE CHECK, and make
the following checks to the cable.  The end of the cable will look like the picture on the
Photo Album page.  The notch locks under the white clip on the connector, just like the
connector under the dash.

The CRUISE CHECK will completely check the functionality of the multi-function switch.  
Plug the adapter into the cigarette lighter/power outlet.  If a proper connection is made
and the outlet has power, a red light will glow on the adapter and the IGN/PWR light on
the CRUISE CHECK box will light.  If no light glows on the adapter, you may need to turn
the ignition on.  Slide the Cruise switch to ON.  The Green light labeled ON will glow if the
switch is good.  Slide and hold the switch to the Resume/Accelerate position.  The
Yellow light will glow if the switch is good.    Press the SET button.  The Red light marked
SET will glow if the switch is good.  If the Red PWR/IGN light was on and any of the other
lights failed to glow as the buttons were pressed, the switch is defective.  
If the switch passed all of the tests, put the cable back in its connector under the dash
and proceed with the next test.

Separate the wire harness at the large connector in the center of the wires.  The
connector left on the CRUISE CHECK box is identical to the connector on the Cruise
Control module under the hood.  Open the hood.  Un-plug the connector from the end of
the cruise module.  The cruise module is usually on the firewall under the hood.  Plug
the CRUISE CHECK into the wiring connector.  Turn on the vehicle ignition.  The PWR
light should glow.  With the PWR light glowing, move the multi-function switch to ON.  
The ON light should glow.  Press the SET button.  The SET light should glow.  Move the
switch to RESUME/ACCEL (R/A).  The RES/ACC light should glow.  If all lights function,
the multi-function switch is good along with all of the wiring to the Cruise Control Module.
 With the ON light glowing, press either the brake pedal or the clutch pedal.  If the switch
on the brake or clutch is functioning properly, the ON light will go out.  The ON light will
come back on as the pedal is released.  If any of these lights fail to glow, and the
multi-function switch has been verified as good, the problem is in the wiring between the
multi-function switch and the cruise module.  Check the switches on the brake and/or
clutch.  

If the switch and wiring checked out as good through the above procedure, the problem
lies inside the Cruise Control module itself.  The only easily repairable part in the Cruise
Control module is the tape that actually does the mechanical work.

Re-connect the wiring harness on the CRUISE CHECK and you will be ready for the next
diagnostic job.

The CRUISE CHECK uses OEM connectors but is not a General Motors product nor is it
endorsed by General Motors.  If you have any problems with CRUISE CHECK or any
suggestions for improvement to the CRUISE CHECK, please call.
Instructions for using Cruise Check
You can use the photos
on the photo album page
to clarify some of these
instructions
Photo hints
HDR, Inc.  Heady Designs & Replications
If you need info on the vacuum
Cruise control, check out:
batauto.com/articles/GM/GMva
ccruise.shtml
Don't have an O'Reilly or
Autozone nearby?  Check
Dorman.com for multi function
switches
.
Search for part numbers:
49273
49277
49284
49286
49288

You can also search by make
and model.