'00 XJ, without factory cruise. Installed steering wheel switches with correct #'s from Ebay, new clockspring, used servo and reservoir that held 15 inches of vacuum each, new hose from manifold to reservoir. Plugged existing plug from OEM harness into servo.
Switch turns cruise light on/off but no other functions on either switch worked on test drive. Dash air vents that did not flow before (air through defrost only) worked initially until tried other air flow settings, then went back to defrost only.
Motor pulls 13 inches steady vacuum when running. Pulled 15 inches of vacuum at manifold end of new hose without check valve, lost 2 inches in 2 minutes. Disconnected small vacuum line from new hose that enters firewall by heater hose entry and capped its new hose tee. Pulled 15 inches and lost 1 inch after 8 minutes. Test drove with small line capped, cruise functions same as before.

Any suggestions as to where to go from here?

Thanks!

Mark

 

Cruise control now works, after 4th junkyard vacuum servo and about $125 total to several junkyards. First 3 either did not hold vacuum or the electronics were not working. Too bad there is no way to bench test servo electronics.
To summarize, bought used steering wheel switches(Ebay, $65), new clockspring(online supplier, don't recall name, $120), used vacuum reservoir(junkyard, $15), new silicone vacuum line and brass tees(Amazon, $26) from manifold to reservoir, and replaced both check valves(Amazon, $14). New brake light switch(Amazon, $10). Modified servo bracket to rotate servo to attach vacuum line without need for an elbow, and eliminated elbow at manifold. Bonus was the replaced HVAC check valve got air flowing to selected dash, defrost and floor outlets via HVAC control panel.
Thanks to forum posters and YouTubers to explain this easy install.

Mark