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Discussion Starter #1
Hi all. Have a Australian Delivered RHD 1997 4.6 HSE with GEMS motor. Car was broken down for 4 years. "Unsolvable electrical problem" was the excuse given.
I bought it and started to explore what the issue was. Fitted a new 640cca battery. Checked all fuses, found all good. Car cranked but dash electrics, windows, power seats, HVAC backlight, central locking were all intemiitent. After several goes motor started but no dashlife. Left car to idle out valve clatter, circulate oil etc for 20 mins.. no motor issues. None. Not even a leak!
Car drove well. Still no guages or windows working. After a week the windows & gauges worked spazmodically but soon car would crank but not start. Appeared to habe locked down, no info display on dash to tell....Started researching online.
BECM....BECM.....Oh Gawd, here we go!
Pulled ECU, Becm, key reader out and sent the lot along with a new key to Injectronics with instructions to recondition all, code to each other & turn off alarm & immobiliser.
All done. They said all A OK now.
Refitted and car started perfect. Still no guages, windows or sunroof. Also noted door locks sketchy, sometimes work good, sometimes not. Sometimes rattle away when car is just sitting parked. It did that before too. More alarmingly, the starter engages randomly when the doorlocks play up. Key is sending a RF signal , tested at local locksmith, but either the car isnt getting it or refuses to acknowledge it so using key in door to lock, unlock.
So....while doing unrelated stuff with car idling I noticed after 15 mins or so the gauges had suddenly come to life...so had everything else.
Happy days for 5 days. Then last night, no dash, just red SRS test light, no windows, locks & starter rubbish again. HVAC backlight out too. Car starts & drives normally otherwise. HVAC fans work, just not backlight. Sometimes randomly during this circus the rear wiper does a swing, just to keep it entertaining.

I have RAVE.
Have removed i spected & cleaned main fusebox under bonnet. Checked & unplugged/replugged all elec connections under bonnet & drivers seat, all sound.
I Removed & cleaned the earth at RHF door frame and heading to earth behind HVAC next. Put a test light on the 4 powered (?) Boltpoles at BECM, each side of fuse box. 3 towards steering wheel have constant power, rearwards one dead, even with key at ON.
Please, Anyone been here before? This is driving me nuts. Vehicle is otherwise in very good condition. 189000km.
Thanks for any assistance people!
 

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Discussion Starter #2
Figured out the 'dead' pole isnt dead, its the earth lol. T'was a late night & a early morning hene.
 

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Three of the supply bolts to the BeCM have permanent power while the one furthest to the rear is BeCM ground so you won't see power on that. Instruments and window switchpack are both fed from fuse number 1, check you have power there. Even though you say you've checked it, with multiple faults I'd suspect the underbonnet fusebox. Not expensive, just replace it but make sure you get the correct one to match your VIN as there are 3 different ones for the V8 with the changeover being 97, maybe someone tried changing it before to cure the problems? Central locking and random unlocking/locking, is faulty microswitches in one of the front door latches.
 

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Discussion Starter #4
Thank you for that useful info Richard, yes during the course of the afternoon reading RAVE I picked up on the BECM earth. I will by a new fusebox as you suggest. Now the car is always garaged out of weather I might as well start with a new one. Thanks again! :)
 

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LEGACY VENDOR
1995-2002 Range Rover P38A
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As you have RAVE and will have the electrical wiring diagrams in there, it will help...

I would also check the wiring (using a multimeter, not a power probe! - as you need to check resistance/continuity down some wires rather than presence of power) on the input feed from the ignition switch (connector between switch and the vehicle loom is under steering column) and the BECM. Specifically checking the Ignition Pos I feed.

I've seen it a number of times where this has failed and caused random issues with things like HEVAC and instruments. May not be your problem, but it's free and pretty quick to check.

If you have seen it working, then that rules out BECM/ECU and all of that, so the issue has to be in the vehicle/wiring somewhere.

As Richard says, the rear bolt on the BECM is the ground connection to it, and jumping door locks is a bad door latch. If you can't get the key to sync/work with the central locking, then a bad door latch won't be helping with that either, as the microswitches need to be working properly for they key to be able to be synced to the vehicle.
 

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Discussion Starter #6
Thank You Marty, really appreciate your input about the Becm being OK if I have seen it working......it was perfect for 5 days across numerous starts & overnight locked without dramas. I assume it is OK then. I have also put the battery on a charger but will have to get a new one. I have been using a brand new one I bought for a V12 Jag I have, thinking it would be heaps, but I have read a bit this evening about the P38 needing atleast 900cca but a 1100cca battery being best. The Jag one is only 640 lol.
This made me wonder if it might have been 'just enough' for a few days but with the starting & shifting vehicle round the garage but no driving has just run it down. Once it is fully charged we will see. If the faults magically dissapear that would e nice. Either way its Monday tomorrow, new battery time.
Thanks again for your help Marty ?
 

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Discussion Starter #7
OK, so further weird outcomes.....pulled the #1 fuse under the seat to test continuity....fuse was not blown, but when I removed it interior lights went off & HVAC backlight comes on, still no gauges or windows etc... I put fuse back in, HVAC goes out, interior lights return. This is with ignition at ON. Maybe a short circuit somewhere? Checking ignition Pos 1 now Marty. Would the door microswitches cause all these things possibly? Central locking intermittent when using the key in door....at moment totally dead but if I remove & replace neg lead on battery quickly it starts working again. Interior lights are same deal.

Ho hum. Rainy Sunday in Regional Australia....Got the only p38 for 500km around....so many possibilities, so few spare parts to swap & rule things out haha
 

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1995-2002 Range Rover P38A
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WHAT you just described is a classic indication of a bad earth.
Start at the battery, use Rave, and find, loosen, clean, and re tighten all earth points you can find.
Been through MG several times, nice spot!
Door locks would not cause this, but a bad earth could mess with door locks as well.
Also, "remove(ing) & replace(ing) neg lead on battery quickly" is just asking for a whole new kind of trouble if you annoy the Becm into thinking it is being stolen........
Doing this, and having brief, "different outcomes" is, however also indicative of a corroded earth point somewhere.
Find 'em, and clean 'em!
 

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Discussion Starter #9
Thanks Bolt, will be hunting all those earths today, and no more disconnecting batteries lol. Yep the Mount is pretty good after living all over Australia with my work....close to SydBourne yet really affordable modern housing, lots of work and amazing secluded beaches only 20KM away. Cheers for the info! ?.
 

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Discussion Starter #10
Just a update have now had Becm reconned, cleaned all Earths & connectors, cleaned fusebox, fitted a new 1000cca battery.
Still same issues.
Shame, is a nice car but this problem seems unfixable.
 
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