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  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech

Cruise Control (which one)????

  • Thread starter Thread starter 67coupe
  • Start date Start date Nov 17, 2008

67coupe

Founding Member
Apr 5, 2002
658
402
93
Huntsville, AL
Nov 17, 2008
#1
  • Nov 17, 2008
  • #1
Cruise control stopped working the other day. Here's what I've tested.

VSS - good
Vacuum release valve - good
No blown fuses
Horn works

It appears I need to replace the servo module. From searching, looks like they are no longer produced. Will have to go the junk yard route.

Question is: What year mustang or vehicle do I need to search for in the local junk yards?

Thanks.
 

backfocus

Member
Sep 3, 2004
254
3
18
Little Rock, AR
Nov 17, 2008
#2
  • Nov 17, 2008
  • #2
I think any mustang 88 to 93 will work, but I am not 100% on that. Mine went out 2 years ago and was lucky to find one of the same year.

Here is a bigger check list if you don't already have it and if you need any more info on checking certain things, I can get that as well. Sounds like you were on the right track though, make sure the cable is tight enough, I had a friends that went out and it turned out the cable had got too much slack in it.

Speed Will Not Set In System

1. Check to ensure proper operation of throttle linkage. If found satisfactory, proceed to step 2. If not found satisfactory, adjust or replace as necessary.
2. Check to ensure proper operation of switch and circuits. If found satisfactory, proceed to step 3. If not found satisfactory, service or replace as necessary.
3. Check to ensure proper operation of vacuum dump valve. If found satisfactory, proceed to step 4. If not found satisfactory, service or replace as necessary.
4. Check to ensure proper operation of stop lamp switch. If found satisfactory, proceed to step 5. If not found satisfactory, replace switch.
5. Check to ensure proper operation of stop lamps. If found satisfactory, proceed to step 6. If not found satisfactory, service lamps.
6. Check to ensure proper operation of clutch deactivator switch (manual transmission only). If found satisfactory, proceed to step 7. If not found satisfactory, service or replace as necessary.
7. Check to ensure proper operation of servo. If found satisfactory, proceed to step 8. If not found satisfactory, replace servo.
8. Check to ensure proper operation of speed sensor. If found satisfactory, proceed to step 9. If not found satisfactory, replace sensor.
9. Check to ensure proper operation of amplifier. If found satisfactory, proceed to step 10. If not found satisfactory, replace amplifier.
10. Examine all connectors to ensure proper contacts.
 

67coupe

Founding Member
Apr 5, 2002
658
402
93
Huntsville, AL
Nov 18, 2008
#3
  • Nov 18, 2008
  • #3
I knew I left some things out.

Brake and clutch pedal switches work properly.

Couple of questions:

1) What's an easy way to check the switches?

2) What's the amplifier?

The last few months before it stopped working, when going up a hill, it would lose a little bit of speed and then aggressively accelerate back to the set speed.
 

backfocus

Member
Sep 3, 2004
254
3
18
Little Rock, AR
Nov 18, 2008
#4
  • Nov 18, 2008
  • #4
Here is a brief description of the system operation, although sounds like you have that figured out. The Amp is under the dash on the drivers side, above the kick panel a ways. It is a black looking box and wires run a short distance out to the servo.


Description and Operation

The speed control system is composed of On-Off, Set-Acc, Coast and Resume switches. The system contains vacuum hoses, servo (throttle actuator) assembly, speed sensor, amplifier, check valve assembly, and depending on model and year, a clutch switch, a manual lever position switch, stop light switch, or vacuum dump valve, an actuator (servo) and an actuator cable.

To operate speed control system, engine must be running and vehicle speed must exceed 30 mph. When On-Off switch is actuated, the system is ready to accept a set speed signal. When vehicle speed stabilizes (above 30 mph), and the On switch is engaged, the operator may depress or release the Set-Acc button. This speed will be maintained until a new speed has been set, brake pedal has been depressed, or the system is turned off.
The vehicle speed may be reduced by applying the brake or clutch pedal and then resetting the speed using the method outlined above or by depressing the COAST switch. When the vehicle has slowed to the desired speed, the COAST switch is released and the new speed is set automatically. If the vehicle speed is reduced below 30 mph (48 km/h), the operator must manually increase the speed and reset the system.

Switch Testing

Testing and Inspection

Disconnect connector at the amplifier assembly, refer to SCHEMATIC DIAGRAMS/ELECTRICAL AND ELECTRONIC DIAGRAMS. Perform the following checks:

1. Connect a voltmeter, part No. 014-00407 or equivalent between the light blue-black lead and ground. Depress the On button and check for battery voltage.
2. Turn ignition Off and connect an ohmmeter between the light blue-black hash lead and ground.
3. Rotate steering wheel throughout its full range while making the following checks:

1. Depress Off button and check for a reading between 0 and 1 ohm.
2. Depress Set button and check for a reading between 714 and 646 ohms.
3. Depress Coast button and check for a reading between 126 and 114 ohms.
4. On models which incorporate Resume, depress Resume button, check for a reading between 2310 and 2090 ohms.

4. If resistance values are within specification but needle fluctuates, remove steering wheel and clean the brushes. Apply a light coat of lubricant ESA-M1C189A or equivalent to the slip rings. If resistance values are above the allowable limits, check the switches and ground circuit.
5. Reconnect the connector at the amplifier.



Cable Adjustment;

1. Remove the cable adjusting clip from the cable housing.
2. Pull lightly on the cable until all of the slack is taken out.
3. Maintain light pressure on cable, then install the cable adjusting clip and snap into place.


Servo testing: Also make sure that you have good vacuum at the servo.

Testing and Inspection

1. Separate the eight pin connector from the amplifier.
2. Connect an ohmmeter between the orange/yellow (circuit 144) and the grey/black (circuit 145) leads at the eight pin connector, refer to SCHEMATIC DIAGRAMS/ELECTRICAL AND ELECTRONIC DIAGRAMS. Resistance should measure 40-75 ohms.
3. Connect an ohmmeter between the orange/yellow (circuit 144) and the white/pink (circuit 146) leads at the connector. Resistance should measure 100-150 ohms.
4. Connect an ohmmeter between the purple/light blue (circuit 147) and Yellow/Red (circuit 148) leads. Resistance should measure 20,000--30,000 ohms.
5. Connect an ohmmeter between the purple/light blue (circuit 147) and brown/light green (circuit 149) leads. Resistance should measure 40,000--60,000 ohms.
6. If proper resistance is not obtained check the wiring and servo separately for damage and replace or service as required.

If you don't have an Alldatadiy account it is very helpful, that is where I found most of this info.
 

67coupe

Founding Member
Apr 5, 2002
658
402
93
Huntsville, AL
Nov 24, 2008
#5
  • Nov 24, 2008
  • #5
Thanks again for your help backfocus!

I wanted to update the thread for future searches. I replaced the cruise control module and I have cruise again...just in time for the holidays.

FYI. This module is from a 4 banger fox. Any 87 - 93 fox module will do.

This is where the module is located.



Here's the module. Basically a big vacuum plunger.



This is what broke. The plunger draws in using engine vacuum and pulls the cruise cable with it.

 

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backfocus

Member
Sep 3, 2004
254
3
18
Little Rock, AR
Nov 24, 2008
#6
  • Nov 24, 2008
  • #6
Great work! What finally lead to it being the cruise module?
 

67coupe

Founding Member
Apr 5, 2002
658
402
93
Huntsville, AL
Nov 24, 2008
#7
  • Nov 24, 2008
  • #7
Thanks.

Everything else tested good. Went to the local boneyard and found a fox with CC. For $30, I thought I'd give it a shot.
 
B

BigBallin

New Member
Mar 5, 2010
9
0
0
Mar 11, 2010
#8
  • Mar 11, 2010
  • #8
posting so i can find this later..i bought a car with cruise that isnt working. so im goin to start checking everything.
 

4G-KDMP

10 Year Member
Jul 23, 2005
935
19
39
CA
Mar 11, 2010
#9
  • Mar 11, 2010
  • #9
^^^Why not just add it to your Favorites?
 

87GT Drop Top

Member
May 1, 2009
500
3
17
South Florida
Mar 12, 2010
#10
  • Mar 12, 2010
  • #10
The servo goes bad all the time. Here is where I got mine. $75 free shipping.

http://cgi.ebay.com/ebaymotors/Crui...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories
 

67coupe

Founding Member
Apr 5, 2002
658
402
93
Huntsville, AL
Mar 12, 2010
#11
  • Mar 12, 2010
  • #11
Are those repo's or OEM?
 
B

BigBallin

New Member
Mar 5, 2010
9
0
0
Mar 12, 2010
#12
  • Mar 12, 2010
  • #12
4G-KDMP said:
^^^Why not just add it to your Favorites?
Click to expand...

had no idea i could
 

4G-KDMP

10 Year Member
Jul 23, 2005
935
19
39
CA
Mar 12, 2010
#13
  • Mar 12, 2010
  • #13
Highlight address... click favorites... click add add to favorites.
 

87GT Drop Top

Member
May 1, 2009
500
3
17
South Florida
Mar 12, 2010
#14
  • Mar 12, 2010
  • #14
67coupe said:
Are those repo's or OEM?
Click to expand...

No idea. Call them up and ask.

AutoPartAuctions.com
12999 Executive Drive
Sugar Land, TX 77478
Phone: 281-565-5457 Fax: 281-565-6636
 
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