Blaine.D Posted April 3, 2018 Share Posted April 3, 2018 I was going though a Cherokee at my local junkyard and saw this yellow box little research later, I found this to be the cruise control module. So I look up to see everything I need and found a website that has the factory manual on the cruise control system. Link to it http://jeep-manual.ru/index.php?page=78 Also Haynes manual for Cherokee/Comanche/Wagoneer on 12-31 has the electrical diagram for the cruise control List of items you will need: Cruise Control Module Control Servo Speedometer Cables Upper and Lower. Upper cable is picture below Speed sensor Turn signal/ windshield wiper stalk with cruise control switch Wire harness Clutch Switch not necessary but is nice if you have manual transmission Vaccum Valve/Brake Switch i believe Vaccum hardline on the servo to the vacuum reservoir Vacuum reservoir (football shape) Finding Parts Most of the parts are behind/under the dash near the gauges and steering column. The Servo is in the engine bay on the passenger side near the closed coolant bottle. Speedometer lower cable is near the output of your transmission/transfer case. Link to comment Share on other sites More sharing options...
Blaine.D Posted April 4, 2018 Author Share Posted April 4, 2018 Problem #1 My valve/switch is missing the internal components.The C4 Corvette uses the same Valve/Switch. The plan is to go back to the junkyard and get one from a Cherokee or a C4 Corvette or i will have to order one. The link below is to the cheapest one i could find new. https://www.oreillyauto.com/detail/b/bwd-3123/lighting---electrical-16777/switches-16486/cruise-control-release-switch-11842/aaeac3c370c7/bwd-brake-light-switch/s749/2611634/1988/chevrolet/corvette?q=cruise Link to comment Share on other sites More sharing options...
Blaine.D Posted April 6, 2018 Author Share Posted April 6, 2018 Went back to the Junkyard today and found the valve/switch in the c4 corvette that was in the yard. The valve/ switch is in front of the brake pedal. Link to comment Share on other sites More sharing options...
Pete M Posted April 8, 2018 Share Posted April 8, 2018 added to the master list Link to comment Share on other sites More sharing options...
Blaine.D Posted April 14, 2018 Author Share Posted April 14, 2018 One of the first item that needs to be changed to allow cruise control to be installed is removing the old speedometer cable that is one piece and replacing it with a two piece cable with a sensor before the gauge cluster. Make sure you find the right lower cable for your Comanche. You will need a longer one for 4wd and a shorter one for RWD. Step 1: Removing the cable from your transmission/transfer case output. Using an adjustable wrench loosen the nut on the speedometer cable and pull out the cable. Step 2: Pull the cable out from underneath until you reach the engine bay. Step 3: Removing cable from gauge cluster. Loosen 4 screws holding dash trim on. The screws are located 2 at the top of the gauge cluster, 1 above the headlight switch and 1 above the cigarette lighter. Remove dash trim. Next, loosen 6 screws on the outer edges of the gauge cluster and warning lights. Now BECAREFUll PULLING THE GAUGE CLUSTER OUT. YOU ONLY NEED TO PULL IT OUT ENOUGH TO REACH BEHIND IT. Disconnect the wiring harness behind the gauge cluster and the wiring harness behind the warning lights. Lastly, press down on two tabs on the speedometer cable to disconnect the cable from the gauge cluster. Move the gauge cluster to safe space for better room to work on the cable and to prevent damage to the gauges. Step 4: Removing Old Cable out of Engine Bay Open your hood and look at the driver side firewall and locate the speedometer cable below the throttle cable. Go under the dash locate the speedometer cable and pop out the rubber plug around the cable. Push the cable through the firewall. The end of the cable may angle up due to the weight of the cable, so you may have to pop the end off to get it through the firewall. Feed the cable down until it drops on the floor. Step 5: Insert the lower cruise control cable into the firewall make sure the rubber plug is in. Small end goes to the gauges and larger goes to the transmission/ transfer case. Feed the cable down the side of the engine and try not to place cable near anything hot or moving parts. On the cable, there is a point that secures the cable to the control arm and pushes the cable onto the bolt. Next feed the cable over transmission mount and transfer case. Insert the cable into your transmission/transfer case. Tighten the nut until secure. Step 6: speed sensor and upper cable install Tighten speed sensor on the end of the lower speedometer cable. Next screw on the upper cable. Step 7: gauge cluster and dash trim install. reattached the two hardness to their locations on the gauges and warning lights. Install speedometer cable on the back of the gauges. Next, push gauge cluster to the proper location and Screw the 6 screws that secure the warning lights and the gauge cluster. Install the dash trim and screw the four screws back into place. Check and make sure the lower speedometer cable is not touching any hot and moving parts. Link to comment Share on other sites More sharing options...
JPBraun Posted May 26, 2018 Share Posted May 26, 2018 Got a question hopefully somebody can help: on a manual transmission is the bracket/mount for the the vacuum dump valve the same for the clutch as it is for the brake? Link to comment Share on other sites More sharing options...
Pete M Posted May 27, 2018 Share Posted May 27, 2018 not sure how many guys will notice a new post in the DIY forum. you may want to start a fresh thread in the Tech forum so more eyeballs will see it. Link to comment Share on other sites More sharing options...
Blaine.D Posted June 7, 2018 Author Share Posted June 7, 2018 On 5/26/2018 at 1:20 PM, JPBraun said: Got a question hopefully somebody can help: on a manual transmission is the bracket/mount for the the vacuum dump valve the same for the clutch as it is for the brake? Based on the brackets that i pull from the junkyard, you can't use the automatic bracket on a manual due to the brake pedal assembly size difference and if you could get it to fit you could not have a clutch disconnect due to the bracket not lining up to the clutch pedal. Link to comment Share on other sites More sharing options...
IronManche87 Posted August 3, 2018 Share Posted August 3, 2018 Where exactly does the control servo bolt to? I've looked for pre dimpled spots and to no avail. Location, location, location? Thanks!Sent from my LGMS210 using Tapatalk Link to comment Share on other sites More sharing options...
Blaine.D Posted August 16, 2018 Author Share Posted August 16, 2018 On 8/3/2018 at 6:18 PM, IronManche87 said: Where exactly does the control servo bolt to? I've looked for pre dimpled spots and to no avail. Location, location, location? Thanks! Sent from my LGMS210 using Tapatalk You will need to drill holes for self-tapping bolts for the servo and mount it. Here's a photo hope this helps. Link to comment Share on other sites More sharing options...
Blaine.D Posted August 16, 2018 Author Share Posted August 16, 2018 Sorry for the long delay. I have been trying to get my truck ready for paint and cause me to delay working on the cruise control. Wiring Harness Install Step 1 Go to the engine bay and remove the plastic plug above the speedometer cable. Step 2 Go under the dash and route the hardness end with the servo connector, ground and vacuum line to servo through the hole. Step 3 route harness to the other side of the engine bay where the servo would mount. Step 4 the ground connector is located inside the thick wire harness there should be a female connector there for the cruise control ground. Step 5 connect the servo wire connector to the servo. Step 6 connect vacuum line to the servo. Step 7 connect the speed sensor to the harness. Step 8 connect control stalk wire to harness step 9 connect control module Step 10 connect the harness to the brake switch. You will need to replace the brake switch to the cruise control version that has two sets of connectors instead of one set of connectors. Step 11 connect to fusebox where it says IGN That's it later I will post how to install the stalk, servo and how to make a bracket for the clutch and brake disconnect Link to comment Share on other sites More sharing options...
eaglescout526 Posted January 26, 2020 Share Posted January 26, 2020 I want to finish this and it deserves to be finished. Installing the stalk is really easy. Remove your old stalk by simply pulling it out. Then take the cruise stalk and feed the wire down the column. I didn't have any issues doing such nor did it get caught up anywhere but you could tie a string to it and feed the string down the column to help pull the wire through. Then push the stalk into the turn signal switch and your stalk is installed. Installing the servo: There are two different servos. 84-87? This servo is grounded out at the bracket which is really smart and doesn't require an extra wire to be sourced in the engine harness. 87-90. This servo has an external ground wire that is located with the servo and its partner is on the main engine harness(pictured above). Take the servo and it should have a mounting stud that you feed into the bracket and thread a nut on to hold it in place. Servo should only go on one way due to the stud and screw that holds the base of the servo on. 84-early 87 servo owners should note that if you grabbed the thicker bracket that mounts on the passenger side fender/wheel well that mounting this one on the firewall will be a challenge as you will have to trim the bracket up so that way the servo won't prevent you from closing the hood. 2.5L owners should be able to mount this bracket with no trimming of the bracket on the fender wall like I did. 4.0L owners have their coolant bottle in the way at that location so you guys might have to get creative or make your own bracket. Important note! If you snag a set up from a 2.8L(generally where the thicker bracket comes from) you might be SOL. I got really really lucky that a dealer had a NOS 2.5L throttle cable and didn't have to figure out how to use the cable that comes with the 2.8L set up so it is imperative to find the 4.0L set ups unless you know where to source a long enough cable with the right hook/clip on it for the throttle linkage. Clutch/brake disconnect/vacuum dump valve. Now there are two styles of the harness when pulling from a junk yard. There is a auto and a manual version. The one Blaine has in this post is a manual version with the dump valve/switch combo. Autos have a clutch switch block plug that bypasses having said switch which is fine, one less thing to get into place when installing. I have an auto set up on mine meaning the clutch switch is bypassed with the plug and only the vacuum dump valve is mounted on the brake pedal like such: This eliminates trying to find or make a bracket for the clutch switch to go on top of the clutch pedal as the valve will open and release all vacuum in the system and the brake switch will shut off the current cruise operation until you push the resume button. So regardless of your trucks trans set up, you can use either auto or manual cruise harness on a manual drive truck. Once the servo, stalk and dump valve are installed, get everything plugged in and ready to go cruise and make some adjustments to the actuator. I will go find the picture I took from the adjustment procedure from the FSM The document included should help with diagnosing issues 1988 Cherokee FSM-cruise control system.pdf Link to comment Share on other sites More sharing options...
Blaine.D Posted January 26, 2020 Author Share Posted January 26, 2020 @eaglescout526 Dang time has slipped from me. I apologized for the lack of responses and updates, other projects came first on the truck before i could get time to finish it and searching for parts. I will finish this thread up today since i recently got it done. Link to comment Share on other sites More sharing options...
eaglescout526 Posted January 26, 2020 Share Posted January 26, 2020 Lol no worries. There’s been a couple people wanting to add cruise and your write up is really good and helpful. And it sat for a year and half so I thought I’d help you out with it and bring it back up to the top. Also I wasn’t sure if you had finished your install or not. Link to comment Share on other sites More sharing options...
Blaine.D Posted January 26, 2020 Author Share Posted January 26, 2020 Switches This is the vacuum switch for the cruise control, there is two styles of them. @eaglescout526 has the earlier style and the one in the photo right above is the later style. The later style can be also found in 80's Gm cars truck etc with cruise control. Both go in front of the brake pedal and the later style plugs into a wiring pigtail that is already there. The bracket mounts to the pedal assembly with one self tapping bolt. Next is the brake pedal switch. This is the same switch but has two additional pins for the cruise control harness to plug into. The two additional pins help to disconnect the electrical part of the cruise control when pressing on the brake. Clutch disconnect switch. This only needed in manual not autos. This disconnects the cruise control when stepping on the clutch. Mounts to the pedal assembly with a bracket and a self tapping bolt. To connect the switch to the harness plug the pigtail with two blue wires with white stripes. The cruise control wiring harness is the same between manual and autos except for a small piece of metal in the pigtail for autos to bypass this switch. simply remove it for install a clutch switch. Vacuum The bigger vacuum line on the right is wrap into the wiring harness. This line runs from the servo to the vacuum switch in front of the brake pedal. The small one on the left runs to the vacuum canister up front located behind the front bummer. Problem one is the vacuum canister there is used for the heater core valve and has only two ports. Here are three possible solutions to have vacuum for the cruise control. 1. Delete the heater value and swap the cruise control in its place on the vacuum canister. 2. Find another baseball shape canister and run a vacuum line with a t connector to share the vacuum between the two vacuum canisters. 3. Be lucky and find a football shape vacuum canister that does the same thing as option 2 but uses one canister. I went with option 3 for my install but all three options should work the same. I ran a t connector from the vacuum supply line to create two lines to go to both ends of the canister. Swap the football cansiter in place of the baseball shape one. One end connect the cruise control line and the other end connect the heater value line. Servo For 4.0L engines. The servo mounts on the firewall. Unmount bracket from the sevo and place it on the firewall approximate near the warning sticker about using the right oil filter. Use a paint marker or sharpie and mark the holes with the bracket. Then drill the three mounting holes. Install bracket with three self tapping bolts. Next install the servo on the bracket. Next connect vacuum lines and electrical pigtail to servo. Then guide the cable over to the throttle linkage through a hole in the bracket that the cable clips into. The end of the cable clips into a pivot point that does not have a cable on it. I am more than happy to take more photos or answer any questions about installing and troubleshooting. Link to comment Share on other sites More sharing options...
Blaine.D Posted January 26, 2020 Author Share Posted January 26, 2020 Cruise Control Module Connect the module with the wide pigtail connector and mount to the lower dash panel with two bolts. If needed there is three adjustment screws to fine tune the cruise control, I will update soon on troubleshooting and adjustment. Link to comment Share on other sites More sharing options...
watchamakalit Posted May 12, 2020 Share Posted May 12, 2020 Awesome thread. I am prepping to tackle this myself. I still need the brake switch and a lower speedo cable. Edit: Apparently I also need the bracket to mount the brake vacuum switch. Any idea where I can source one? Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 12, 2020 Share Posted May 12, 2020 4 hours ago, watchamakalit said: Edit: Apparently I also need the bracket to mount the brake vacuum switch. Any idea where I can source one? XJ's 84-90 or you might have to make one yourself. These brackets are getting harder to come across. Link to comment Share on other sites More sharing options...
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