Renix Cruise Control Help

[JPBraun]

I’ve been trying to add cruise control to my 89 MJ 4.0 5-speed with parts pulled from junkyard XJ’s. I believe I have everything and have tried a bit of troubleshooting but can’t get it to work. Any help or insight would be much appreciated. 

 

Here’s the install list:

• cruise control wire harness 

• cc harness plugged to “ACC” in fuse box on truck with inline 4 amp fuse unbroken

• speedo cable switched to two piece with speed sensor

• speed sensor plugged to cc harness

• brake switch swapped out for the one with extra terminals - plugged to cc harness

• brake sensor (aka vacuum dump valve) & bracket mounted and properly adjusted on brake pedal with the sensor plugged into connector from stock wiring harness and big vac line going to servo 

• servo mounted with cable connected to throttle body and connected to both cc harness plug and stock wiring harness plug

• yellow cc module plugged into cc harness 

• cruise equipped turn signal lever installed and plugged into cc harness

• football-shaped vacuum reservoir in place of the ball one with small vac line running to servo

 

Here’s all I’ve done in terms of troubleshooting:

• I have multiples of the module, speed sensor, servo, and harness and have tried various combinations excluding the harness because I know it needs a repair. 

• I have checked the resistance of the turn signal lever as instructed in the FSM and it seemed to all check out so I think no wires are broken in it. 

• Small vac line at servo sticks to my finger when pulled off servo so it has vacuum but I’m not certain it’s enough. Any recommendations on a vacuum measuring device?  All AC conrtrols work and reservoir seems to hold vacuum. 

• I have also plugged off the large vac line at the servo to eliminate the brake dump valve if it was the leaky culprit 

 

Also, if any one has a spare sensor and bracket for the clutch petal on a manual transmission I’d love to buy one. 

 

 

[Ωhm]

CC Module adjustment set screws (3) should be centered. If vehicle is up on jack stands CC might/will not engage. Vehicle should be road tested for proper engagement (CC module needs feedback).

[JPBraun]

Thanks. I have messed with the adjustment screws on one of the modules. Maybe I’ll put the other one in and play around with it. All testing has been done on the road above 40 mph. 

[Ωhm]

14 hours ago, JPBraun said:

• cc harness plugged to “ACC” in fuse box on truck with inline 4 amp fuse unbroken

Using 88 Electrical Manual:

Single connector should be plugged to IGN (lower center of fuse box). Now I agree with you, if ACC is hot in RUN then it shouldn't matter, but it will not see hot in RUN/START (I1). The 4A inline fuse comes off the brake switch.
 

[JPBraun]

I guess I wrote my original post from memory because when I looked at my fuse block it’s actually plugged into IGN. Thanks for taking the time, Ωhm. Seriously, very helpful.