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Repair1014U, Shop Owner
Category: Car
Satisfied Customers: 709
Experience:  Diagnostics, Electrical
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Fuse Box..becm fusebox.. Then the power windows..locks../were blown

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Repair1014UHello.Hello. After trying to figure out my BeCM shorts over several weekends, I reluctantly took my Range Rover to the dealer...After not being able to diagnose/troubleshoot anything, they presented me with an estimate for over $6,600! (6 Grand U.S.!) I am asking for any thoughts, ideas, or experience related to testing/diagnosing the BeCM and Engine Fuse Box (Z238 and P125a) on a 1997 P38a...I accidentally shorted out a wire that was attatched to the hot side (non-fused/unprotected) of a fuse that was inserted in Fuse 7 position of the BeCM Fusebox.. Then the power windows, sunroof, locks, seats, mirrors, radio, and HVAC stopped working and the Dash displays Fuse 7/8/9/10/20/22 Failed....None are/were blown, Had the BeCM Remanufactured, istalled it...nothing had changed? So my thought is that the BeCM isn't getting power from the Eng. Fusebox because all the areas that do not work (p. wins,etc.) are the same areas that are showing as blown on the dash. In other words, internally it is sensing no power in those area that are fried in the Eng Fusebox that is feeding it...Any suggestions or ideas are going to be most appreciated!!!.Thanks a bunch, XXXXX XXXXX
Hi Brian,

sorry for the delay, wow you are having one thing after another with this vehicle. The dealer is crazy with there prices.

Brian here is a report out about a bad ground connection, check it out and let me know how you did.

Thank you
Customer: replied 5 years ago.
Hello Repair1014U, Good Evening and Thanks for the quick expertise!...I am working on cleaning up all those grounds...Is there any info. available on diagnosing P125a (Eng. Fusebox) failure or on how power is supplied to BeCM areas that deal with/control Fuses 7-10, 20,22? Ya, I was really dissappointed with the dealership experience but I was getting tired of friends/family telling me I was nuts for keeping this truck....Tough Times never last, Tough People Do, etc! I'm in this for the long haul and I will figure this out (God willing with your help:) without spending crazy money.
Hi Brian sorry for such a long delay getting back to you, been very busy and sorry about that. I will be on tomorrow in the afternoon.

When you are talking about P124a are you referring to the code P0125? If so this is the

P0125 Insufficient Coolant Temperature for Closed Loop Fuel Control.

Do you know know what the fuses 7 10 20 22 are for and I can search that way.

Please let me know I will be glad to keep helping you.

Repair1014U and 2 other Car Specialists are ready to help you
Customer: replied 5 years ago.

Hey Repair1014U,

Well Semi-Great News, I had my some of my truck working for about 45 mins yesterday....MaxiFuse#5 feeds the was only putting minimal voltage to it. I replaced it and I had HVAC and radio,etc then it quit again. When I shorted that wire before, It started to blow that fuse and that's why everything went dead....Just now it's doing it again and I think it's fuse 7 or 8...I cannot get to them now but will tomorrow. My windows I think it's the switch pack,etc....I cleaned all the grounds to perfection and put dielectric grease on them, near the coolant tank under the hood (where they were all kinda not real good)...Good call on that as I'm sure that is contributing to all these issues. Oh, P125a, is Range Rovers coding for the engine fusebox, as is Z238 is the BeCM module, etc....They have everything coded for universal identifaction through it's product line....Everything, connectors, splices, grounds, it's pretty neat how it all works, even though I have been trying to study/learn the schematics you sent me, it's a lot to take in. Gotta roll, goodnight and Thanks again for all your help Mr. Repair1014U! Brian....Also, don't you at least have a real 1st name? It's not like I'm some mad computer genius hacker guy, Kidding!

My friends call me Hot Rod. Thank you again Brian so much. Electrical problem are such a time consuming and a headache. Let me know if you need more help and thank you for the accept and great bonus. Have a great day.
Customer: replied 5 years ago.
Hey Hot Rod! Good Evening and how are you doing. Do you know if there is a way for the BeCM to switch off ( or deselect ) the power windows on my '97 Range Rover4.6HSE? Remember, I told you about having the BeCM remanned, could the windows be unselected while they rebuilt it by accident, etc? I had power to switch pack, so I thought it was my switch pack assy...I put in a new switch pack, and I still have no windows. Do you have any other ideas about the power window situation? I will ask another question on here when I'm sure you're online, so you can answer it and get credit. Are you familliar with the front hubs on the Ranges? Thanks again, XXXXX
Hi Brian,

Did the windows work for awhile and then stop work after the BECM was replaced?

If so you need to first check the fuse and if there is power there.If no power then check the junction box fuse. If you have power at the fuse box then check for power at the switch. If no power at the switch then you need to check the Becm pin outs for power coming out of the BECM if no power coming out and there is power going in the BECM needs to reprogramed.

I will be on and off line this weekend. If you give a time I could be on line and please address it Repair1014u, this way the other experts do not help you. I can help you with that other problem

Thank you for getting back in touch.
Customer: replied 5 years ago.
Hey Hot Rod, Good Afternoon. I need to ask you which connectors and which pins do I need to test to verify that my BeCM is getting a signal from the switches, etc? Then where do I test at the eng fusebox, as well as the BeCM for signal out>? Thanks, Brian
Hi Brian,

here check out this web site for your Becm.

If it did not work type in on Google
"1997 range rover becm pin out"

Then it is the first one that says:

Demystifying the BeCM - Range Rovers


Let me know if you have any trouble.


Thank you Brian and I hope you have a great weekend.


I am here if you need my help

Hi Brian,

here is some more pin outs for you

Customer: replied 5 years ago.
Hey Hot Rod, I am asking what connectors/pins to test to diagnose all the things you told me to check...I am scared to ruin a $3000 unit testing the wrong pins, etc. Some inputs use + and some are - that's why I am asking you what Exactly to test. I need to check for signal in/out of BeCM from switch pack, cruise, sunvisors, and central locks. Also, is there any way to check out the relays that are internal (read:unserviceable) BeCM units or run an actuation test on them, (BeCM int. relay #7 or 9)? Because they use serial-bus communication it complicates things exponentially when looking to check inputs/outputs!!! Let me know what you think and thanks as always, Brian
Good morning Brian,

The pin locations are all on the chart I gave you. Only test one pin at a time, like test the sunroof you can use a volt meter ground the the ground to the vehicle and test the pin for the sunroof and have someone press the button, if you have power voltage coming out then that is ok with the Becm and you either have a break in the line or the switch is bad.

I am going to opt out becuase I do not have the test procedure for the internal relays and maybe another expert can help you with this.

Good luck Brian you are a great customer.