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Greg Smith Power door locks writeup PRE-1991

Re: Greg Smith Power door locks writeup

I have a 93 XJ Country (300,000 miles) with power door locks. The front doorlocks generally work well. The rear door locks do not work consistantly. In cold freezing weather they work seldom. In warmer weather I can get the locks to activate by using the electric switch about three times in a row. The lock moves slightly more each time until the third time when it moves to the full unlock position. The lock is also hard to operate manually from the inside manual button.
Would this be an electrical problem or a mechanical problem? Bad electrical relay? Is the lock worn out or just rusty/in need of lube? Is the lock electrical solenoid bad?
What are the steps to diagnois the problem.
Thanks everyone!
 
93 XJ Country power door locks not consistent

I have a 93 XJ Country (300,000 miles) with power door locks. The front doorlocks generally work well. The rear door locks do not work consistently. In cold freezing weather they work seldom. In warmer weather I can get the locks to activate by using the electric switch about three times in a row. The lock moves slightly more each time until the third time when it moves to the full unlock position. The lock is also hard to operate manually from the inside manual button.
Would this be an electrical problem or a mechanical problem? Bad electrical relay? Is the lock worn out or just rusty/in need of lube? Is the lock electrical solenoid bad?
What are the steps to diagnois the problem.
Thanks everyone!
 
Re: 93 XJ Country power door locks not consistent

Clean and lube. The 93 comes with separate lock and unlock relays (lower dash panel in front of your right knee) so the famous Greg Smith fix (that I used successfully on my 85 -- thanks, Greg!) does not apply per se. I assume that the newer system might still benefit from running larger wires to the rear locks but the difficulty in manual locking is a sure sign of a gunked up mechanism.
 
Re: Greg Smith Power door locks writeup

Thanks for the reply. I'd rather start with the most likely fix first, and that sounds logical to me. Appreciate your opionion as someone who has worked on the related Greg Smith project.

This is a great forum! I appreciate all the knowledge out here!
 
Re: Greg Smith Power door locks writeup

OK, I want to do this to my 90 that has a Viper security, remote start, and remote door locks.

All of the doors are non functional except the hatch, go figure!

Since I'm use to working from schematics, does anyone have any I can get e-mailed to me. I get confused when I read "cut this LG wire and hook it up to this terminal.....etc" I work better from a wiring diagram/schematic.

PM me for my e-mail address if you have a schematic, thanks!

Jon
 
Re: Greg Smith Power door locks writeup

Hey guys

Need a little help with this- anyone have pictures of the wiring inside the passenger kick panel of a 1990? i removed it and see a rats nest of wiring everywhere. im not exactly sure which connector im supposed to be splicing- i have a three wire bundle (light green, tan and black) that has a small connector (comes from the remote sensor in the headliner i think) and a big harness that goes to 2 relays (keyless relays i think).

i can take a couple pictues tonight and post them, but until then, id appreciate any help.

REally looking forward to getting my doors working again.

A kinda related question- if i hook up an aftermarket keyless system (i dont have a fob and a replacement is way overpriced) can i just splice intot hose wires coming down from the original sensor- the 3 wire green, tan, black bundle? If so, that would be awesome

Thanks for all the help
 
Re: Greg Smith Power door locks writeup

Got it all working great- locks are slamming shut now. Its awesome. No problem finding the green and tan wires in the end. Was pretty obvious. I had everything all wired up, with only the 12v power line to connect to the battery. Popped the hood, closed the door then stuck the red wire on the post to hear a very satisfying clunk as all the doors locked. The joy lasted about a minute until i realised i was going to have to call AAA to help me get my keys back from off the drivers seat...:laugh:

all good though. Just delayed me in getting my back up lights wired in, but this way, i get to play with JC tomorrow too...
 
Re: Greg Smith Power door locks writeup

Here is a current version of the writeup.

Power Door Lock Fix for Reluctant Locks on Pre 1991 Jeep Cherokees
(for post 90 models with a similar problem I woud check the relays in the passenger side kick panel)

The Problem:

Some (usually not all) of the power door locks stop working, or more commonly work inconsistently on the lock and/or unlock position. The problem usually starts when the Jeep gets older and the locks become stiffer. Cold weather seems to cause the most problems. The rear hatch and rear doors seem to the most troublesome since they are on the end of the circuit and experience the largest voltage drop.

The Cause:

The cause is a design flaw which causes a loss of 2 volts. As the Jeep gets older and the locks become stiffer and the connections develop some resistance the amount of voltage that gets through the system is no longer enough to work the power locks near the end of the circuit. With the pre 1991 wiring all the power for the power door locks passes through the passenger door lock switch regardless of whether you trigger that switch, the driver’s side door switch or the remote keyless opener (if you have it). Power leaves that switch going to the door locks through the tan wire for unlock and the light green wire for lock.

The power goes from the passenger door switch to a splice in that door for the power lock in that door and then goes out the door and into the kick panel in front of the door on the passenger side. By the time the power gets to the kick panel it has lost about 2 volts. I replaced my passenger side switch suspecting a bad switch but still lost 2 volts out of the switch. I then did a full continuity and resistance test on the switch per the factory service manual and found no problems. I have never figured out why this happens but apparently Jeep could not either since they changed the wiring starting in 1991 to compensate for this problem. (Note the wiring change can be done like the post 1990 models but the fix I provide below is a lot easier in my opinion.) After the now lower voltage gets to the passenger side kick panel it goes under the carpet and over to the driver’s side and hits a master splice under the front floor carpet for the wires going to the driver’s side front and rear doors and the passenger side rear door. I unwrapped the tape around the splices and checked all the splices and they were clean and tight. Then I measured the voltage at the remaining power locks. By the time the voltage gets through the master splice is loses another 2+ volts and is not enough to power the locks consistently when they become stiff from old age or cold weather.

The Fix/Repair:

First make sure you are getting around 12 volts of power to your passenger side door switch directly or when you trigger the lock or unlock switch from the driver’s side or by the remote. You can test the voltage with a multi-meter at the wire harness connector in the passenger-side kick panel where the dark green, white and red wires go into the front door.

Assuming you have a full voltage supply to the passenger side switch, the fix is to install two relays in the passenger-side kick panel on the lock and unlock wires coming from the passenger side switch. The relays will increase voltage back up to 12 volts to compensate for the loss caused by the passenger side switch. With the voltage increase provided by the relays, the voltage at the remaining power door locks is increased by approximately 2 volts, enough to power all the locks, even in cold weather. This of course assumes that no wiring problems exist from the splices to the door locks. If you still have a problem at a particular door lock measure the voltage and make sure it is over 9 volts. With my fix it should be closer to 10 and perhaps 9 at the rear hatch.

The relays to use are 5 blade, 12 volt, 30 amp minimum rated relays with blades marked 85, 86, 87, 87a and 30. These relays are the same as those used for the keyless remote relays found in the passenger-side kick panel so you may find them cheap at the bone yard. You can also find them in automotive electric supply stores. Look in the section that has lighting upgrade supplies. For an easier install it is also best to buy wiring sockets that fit the relays. Here is a link to partsexpress.com an online supplier that has relays and sockets at reasonable prices. I used 2 bosch relays # 330-070 and 2 sockets # 330-075 (although 1 dual socket 330-078 could be used I believe). http://www.partsexpress.com/webpage.cfm?&Webpage_ID=3&DID=7&CAT_ID=47&ObjectGroup_ID=31&SO=2

Here is how I did the wiring: I used the two 12v relays. They have 5 blades: 86 is trigger pwr from the passenger dr switch; 85 is ground; 87 is the new pwr source; 30 is the path to the lock and 87a is to ground (in this application). I cut the Lgreen and tan wire about 5 inches forward (toward the front of the Jeep) of the wire harness connector that connects the wires to the wires coming out of the passenger frnt dr. In this example I attached the tan unlock wire coming from the passenger frnt door to 86 and 85 to ground; 30 is attached to the tan wire going to the door locks; and 87a is to ground. I used the new 10 gauge pwr line I had previously run to the battery/starter relay post with a 30 amp inline fuse. You can take off pwr from a splice on the red pwr going into the passenger door instead. (The same approach is used for the lgreen wire using the other new relay for for the lock circuit.) The key to making this work was 87a to ground. When the lgreen or tan wire are not in pwr mode they provide ground path to ground through the driver’s side switch. With my new relays I substituted a new body ground instead. As a result I increased voltage and created new better grounds. The locks now all slam open and closed even in very cold weather. Hope this helps. At least 30 people I have heard from have done this mod with great success. Greg


will this work on a 1997?
 
Re: Greg Smith Power door locks writeup

Quick answer is that 97s already have relays.

What problems are you having?
 
Re: Greg Smith Power door locks writeup

As stated in the write up post 90 xj (including your 97 I assume) already have the relays for lock and unlock in your passenger side kick panel. If you are having a problem with a no lock or unlock after first confirming your fuse is ok then check out those relays. Greg
 
Re: Greg Smith Power door locks writeup

I am out of Jeeps now. My 89 XJ served me, the family and two daughters through College well. We had it since new. But it was well worn and time to move on and cash for clunkers and the need for a light weight newer flat toweable high mpg vehicle for my motor home to tow meant my XJ went to XJ heaven. :angel: I probably will not be on the forum in the future since I no longer have a Jeep. I am very happy my writeup is helpful to many of you. Those locks can be very annoying. Like we don't have enough stuff bugging us? Not! Best wishes to you all. :wave1: Greg
 
Re: Greg Smith Power door locks writeup

Thanks Greg, for the writeup and all your help. It worked for me!
 
Re: Greg Smith Power door locks writeup

I am out of Jeeps now. My 89 XJ served me, the family and two daughters through College well. We had it since new. But it was well worn and time to move on and cash for clunkers and the need for a light weight newer flat toweable high mpg vehicle for my motor home to tow meant my XJ went to XJ heaven. :angel: I probably will not be on the forum in the future since I no longer have a Jeep. I am very happy my writeup is helpful to many of you. Those locks can be very annoying. Like we don't have enough stuff bugging us? Not! Best wishes to you all. :wave1: Greg


I hate to see you go Greg but you know there are still a bunch of great XJ's for sale around our area. I finally got around to doing this upgrade to my 90 and I'm impressed thoroughly how well the locks work now!!

Thanks for all of your helpful input here on NAXJA
 
Re: Greg Smith Power door locks writeup

now the door locks works fine..switching relays....but some other relays were tested
 
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