Okay, so I decided to replace the fuse box on my 97 P38 4.6 after finding two of the BeCM posts on the circuit board had come adrift from the solder joins, causing the usual "Fuses Blown" and other usual warning messages. Prior to this, all earth points had been cleaned, cables from the alternator and battery beefed up and replaced, battery charged on a 3 stage charger, and all seemed to be fine apart from the fault messages.
While I was at it, I also decided to have a go at repairing the RH blend servo and RH recirculation servo, have a look at the poor visibility of the message display on the instrument panel, replace some lamps in the dash switch pack, replace the cruise control switch on the brake peddle and repair various broken plastic parts that had suffered from age.
All seemed to be going well. Cleaned all the contacts on the multi-plugs and BeCM lugs for the fuse box, reconnected everything, charged the battery on a 3 stage charger. Found both blend motors were actually working when I used a 9V battery on the multi-plug, Removed the front and rear covers of the instrument panel, cleaned years of dust on the inside of the clear plastic front cover, couldn't seen anything to check on the message display, replace a few lamps for good measure, then reassembles everything. Now, it's worth pointing out that AC was working fine (cold) before I started, apart from the book symbol and servos.
I put the key in the ignition, turned to the second position and got all the window/sunroof not set messages AND alternator fault! Set all the windows and sunroof. Cleared fault codes and calibrated the servos with Nanocom. No book symbol!!!!! Started the engine and all seemed fine. However, the AC was not engaging but the condenser fans were running. The temp gauge didn't move even after 5 minutes. Switched off the engine and notice the temp gauge did move to the far left as usual when ignition is off, and moved very slightly when ignition was on.
I rechecked the connections of the multi-connectors on the fuse box, check seating of fuses and relays associated with the AC, all seemed fine, but the compressor clutch wouldn't engage. Had the dash switch pack off again to check the interior temp sensor connector, had the instrument panel out again an checked the connections just in case that was the cause of the temp gauge issue.
So, any ideas as to why the AC clutch won't engage, compressor fans run, temp gauge doesn't read and the alternator fault message which only come on when the ignition is in position 2, goes off when the engine starts and there is no reminder message when the ignition is switched off? So disappointing, as it was all going so well.
ChatterBox
Hi Mate
Have you tried these checks ?
Sticky: Electrical Troubleshooting Updated 2010
Seems like a voltage problem somewhere, what year is your P38?
I just replaced my fusebox and my A/C was temperamental before but now it seems to be dead as well
Steve
Thanks Steve. Yes, I've gone through all the electrical checks several time over the past few months for other issues I was having. All seemed fine afterwards, apart from when I reconnected the 3 BeCM power feeds to the old fuse box I managed to break the solder joint on 2 of them, hence the 'Fuse Blown' messages and the reason for changing the fuse box. So the long and short is that everything was working prior to changing the fuse box and removing the instruments and switch packs to sort out the servos. I've gone back into the dash to see if there was anything astray, but all seems good. The temp gauge and 'alternator fault' are the two that really have me foxed.Originally Posted by TheTree
Hi Mate
Have you tried these checks ?
Sticky: Electrical Troubleshooting Updated 2010
Seems like a voltage problem somewhere, what year is your P38?
I just replaced my fusebox and my A/C was temperamental before but now it seems to be dead as well
Steve
ChatterBox
It almost sounds like you have a faulty fuse box very weird!
Not sure what to suggest except swapping it with another one perhaps?
Steve
Others have questioned if I used the correct fuse box for the year of the car, but they are identical, and the replacement is new and original LR.
ChatterBox
mate
Have you cleaned the earth connector behind the drivers kick panel (the one with the bonnet release in it) and the white connector just near it?
Steve
Yup! I've done them all. But I tell you, I'm going over them AGAIN at the weekend. I must say that the more I think about it the more it must be an earth fault somewhere. What I omitted to mention was that a few weeks ago I have a leak on the coolant header tank where the pipe from the rad goes in, and lost 95% of my coolant. Only discovered it when I got home and the wife asked what was the hissing sound. I have ringing in the ears, so couldn't hear it! The temp gauge didn't notice either. I recon that the steam must have impregnated into more places than I care to think about. Fun times ahead!
ChatterBox
I would also double check the connectors under the fusebox and clean them with something like Deoxit especially if you have had steam blasting around that area
Steve
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