Power door lock fix for pre-91 MJ/XJ

[87MJTIM]

If you have power locks and find that the driver's door just will not lock or unlock when you hit the switch, you should do this upgrade/fix to your wiring.  

 

I found this write up on both JeepForum and NAXJA.org.  I will paste a link to the NAXJA since it is a little more concise in the write up.

 

https://naxja.org/threads/greg-smith-power-door-locks-writeup-pre-1991.1874/

 

 

I followed Greg's instructions except for the power source.  I spliced into the main power coming over from the driver's side and used a splitter from NAPA (part #784473).  

 

I cut the light green and tan wires and crimped on spade female connectors.  These went directly to the relay terminals.  I should have added more wire so the connections aren't as stretched.  I did add wire to the power feed, as the photo shows.  It isn't pretty, but you cannot see it with the kick panel in place.

 

 

Verdict: DO IT! I now have working door locks from the driver's side. 

[eaglescout526]

I’ll do ya one better.(not to one up, just a simple mod I did before adding my keyless)
 

I did the step up transformer mod thats used for the power windows and applied that to the lock circuit. Granted I did this to my XJ so everything including the hatch will unlock now but ohhhh man do they work. 
 

 

Granted I did try this mod on my MJ when I had the relays, but I ended up deleting the relays and they work good. 

[Htchevyii]

39 minutes ago, eaglescout526 said:

I’ll do ya one better.(not to one up, just a simple mod I did before adding my keyless)
 

I did the step up transformer mod thats used for the power windows and applied that to the lock circuit. Granted I did this to my XJ so everything including the hatch will unlock now but ohhhh man do they work. 
 

 

Granted I did try this mod on my MJ when I had the relays, but I ended up deleting the relays and they work good. 

I've been thinking about trying that in the XJ locks. I added one to the power windows a few years ago with excellent results. I've never got around to trying to hunt down the power supply for the locks.

[eaglescout526]

36 minutes ago, Htchevyii said:

I've been thinking about trying that in the XJ locks. I added one to the power windows a few years ago with excellent results. I've never got around to trying to hunt down the power supply for the locks.

I used the same exact supply that was recommended for the windows. I’ll probably end up using that too when I add power windows in the future. 

[ghetdjc320]

What voltage are you stepping up to? 

[eaglescout526]

I was gonna type 16v but I guess I got one that is 19v. But I can’t see it putting out 19v 100% of the time nor getting 19v to every lock solenoid. 
 

I mean they are just simple motors. 

[ghetdjc320]

6 hours ago, eaglescout526 said:

I was gonna type 16v but I guess I got one that is 19v. But I can’t see it putting out 19v 100% of the time nor getting 19v to every lock solenoid. 
 

I mean they are just simple motors. 

When I swapped in electric windows, I powered them with an 18v drill battery to test them and the speed was awesome. At 12v it was functional but much slower. I ended up programming the alternator voltage control up to 14v and all of the accessories now run very well. But I’m still curious how a 19v would do.