Door lock troubleshooting 86 series 3

Can anyone refer me to a door lock trouble shooting guide for series 3 ? I have tried to find such things on this new site but cannot. I have read several manuals but am still confused where to find the door lock relay (relays?) and hidden inline fuse (protection thermal device?)

The Jaguar Series III XJ6 S57 Electrical Guide has great information on the electrical components in the car, where they are located, where the connectors are, where all the relays are, all the wires and their colors. I purchased my hard copy on eBay but others have posted recently about an online source where it can be downloaded. Just search the archives for “S57 Electrical Guide”.

The Jag-Lovers archives is probably a good place to search for posts from others over the past 20 years or so about door lock problems. Your 1986 would have the newer Kiekert motorized locks instead of the earlier solenoids.

You don’t mention the problem you are having, but the usual remedy for lazy or inoperative door locks is to remove the door panels, clean and lubricate the mechanical linkages of the old hardened grease, and lubricate the linkages with new grease. That has always worked for me.


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Thank you Paul for your recommendation of the Guide. my locks and all linkages have been gone thru, cleaned and greased some several years ago. They all worked fine till one day…nothing; no response from the drivers door key except to mechanically open the driver door. I have the trim panel off and the door switch out but do not know yet how to test it to see if that is the problem. I’ll also check the old site archives as you suggest.

Also check the XJ Frequently Asked Questions (FAQs) on the old website. Seems to me there were some FAQs about the Kiekert door locks burning out, but I could be wrong about that.


Since yours in an '86 with the Kiekert system, as Paul pointed out, you won’t have the lock relays.

And you’ll probably have an inline fuse rather than a circuit breaker, likely in the area of the RH fuse box (I’m a little foggy on that) on brown and brown/blue wires.


You have the Kiekert motors, as Paul says - no relays, no thermal fuses…

First step; access Auxiliary fuse box on passenger side. There is either an inline fuse (dig around) or fuse #14 5A

…change fuse and test locking. However; while the manual says a 5A fuse - check the value of the fuse you removed. Methinks that rating is too low - replace like with like…

Warning; if some, but not all, of the locks, door or boot, operate and one or more fails; do NOT(!) proceed without further checks. The control unit, in the driver’s door, may have failed - it should normally give a brief(!) burst of power to the motors…

If failing; the control unit may send a too long pulse, causing the fuse to blow - and may burn out one or more motors. If fuse is then replaced motors may burn out in turn - expensive…

If the replaced fuse holds and all locks operates normally - keep an eye on the situation.

If replacing the fuse makes no difference - you need to test the control unit. To be explained if required…:slight_smile:

xj6 85 Sov Europe (UK/NZ)

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I have resolved the problem with much appreciated help; I incorrectly assumed that the manual was correct that power mirrors and the door locks were on the same fuse. Actually the locks were on a single in line fuse which was blown. Even so something did happen to blow the left rear door Kiekert door motor so I will need one of those. Everything else does work again on the locks.
Scott Roskam

I did reset the adjustment on the control unit to insure the neutral spot was in the correct location centered with the key lever so I hope no more motors will be affected.

What manual were you using?


I still think you should verify proper control unit function, Scott…

While a motor may fail and cause the fuse to blow; a faulty control unit may power the motors for too long, causing both a blown fuse and a motor burn-out. With a repeat of a long pulse; with only 4 motors the current flow is lower delaying fuse blowing - and another motor may burn out…and another…

As a minimum; when locking/unlocking - check that all remaining locks have operated…

To check control unit; remove drivers side A-pillar panel to access connections. You will find a connector with an orange/green and orange/red wires. Disconnect and connect a test lamp across the door side connector and operate the lock. The lamp should light for approximately 2 seconds…

An off-centre control unit will not in itself cause motor failure or blow fuses. It will only fail to either lock or unlock the doors - or to lock the boot…

xj6 85 Sov Europe (UK/NZ)