88 XJ6/XJ40 VCM problem
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88 XJ6/XJ40 VCM problem
Hi all,
I just joined the forum after acquiring an 88 XJ6/XJ40. Not quite sure of the nomenclature so hopefully one is correct.
My problem is that when I turn on the key the VCM box is supposed to light up and go through the various warning lights. Mine only shows just the outside yellow border and nothing else. It goes away when the engine starts. Unfortunately the lights for the fuel gauge, temperature, oil pressure, odometer, etc. are not coming on at all. The speedo and tach are working fine.
Anyone know of how to go about fixing this problem? I've checked all fuses and they appear intact. I am not an especially mechanical person so if your answer can be in layman's terms as much as possible it would be most appreciated.
I am posting this on both the general technical as well as the 88-94 XJ6 forums.
Any and all ideas are welcomed!
Thank you,
Rick
I just joined the forum after acquiring an 88 XJ6/XJ40. Not quite sure of the nomenclature so hopefully one is correct.
My problem is that when I turn on the key the VCM box is supposed to light up and go through the various warning lights. Mine only shows just the outside yellow border and nothing else. It goes away when the engine starts. Unfortunately the lights for the fuel gauge, temperature, oil pressure, odometer, etc. are not coming on at all. The speedo and tach are working fine.
Anyone know of how to go about fixing this problem? I've checked all fuses and they appear intact. I am not an especially mechanical person so if your answer can be in layman's terms as much as possible it would be most appreciated.
I am posting this on both the general technical as well as the 88-94 XJ6 forums.
Any and all ideas are welcomed!
Thank you,
Rick
RE: 88 XJ6/XJ40 VCM problem
Hey there absoluteze n welcome to the forum.
I am not your best source of info for sure on thse models, that'd have to be Ken, Jose and maybe Jag genius.
I've done a bit of research however and come up with this. Not sure if it'll help or not but sounds like you're about willing to try anything.
VCM Display
Intermittent loss of the Vehicle Condition Monitor display.
The most common cause of this is a failure of the printed circuit solder connections to the transformer which supplies the high voltage to the fluorescent display, especially if a thump to the front top edge of the instrument momentarily brings on the display.
Remove the Instrument panel completely, take off the back, take sensible anti-static precautions remove the small circuit board at the opposite end from the monitor display and you will see the transformer. Examine the pin connections with a magnifying glass as the cracks can be difficult to see re solder and all will be OK.
The most common cause of this is a failure of the printed circuit solder connections to the transformer which supplies the high voltage to the fluorescent display, especially if a thump to the front top edge of the instrument momentarily brings on the display.
Remove the Instrument panel completely, take off the back, take sensible anti-static precautions remove the small circuit board at the opposite end from the monitor display and you will see the transformer. Examine the pin connections with a magnifying glass as the cracks can be difficult to see re solder and all will be OK.
Hope it helps
Good luck
Jim
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Joined: Feb 2007
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From: Chicago/Carbondale
RE: 88 XJ6/XJ40 VCM problem
Before u go removing the Instrument panel check the relay boxes and the circuit boxes. Idk how different an 88 is to an 93, but I'm assuming urs uses relays and circuits...there should be circuit boards on the door side of the front seats.
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RE: 88 XJ6/XJ40 VCM problem
Hello, I'm the poor bloke that's working on Absoleteze's XJ40.
If this helps anyone point me in the right direction, the VCM quit working when the battery was changed out. Before then all was perfect. Now only the speedo,tach, and warning box work, outline only-no icons orprintout.No odometer, oil pressure, volt, temp, fuel, gear selector readout. I have checked all the relays under the right scuttle, all 3 fuse locations to no avail. If I remember correctly the VCMs were vary voltage sensitive and would fail due to voltage spikes. Does my memory fail me?
Also this poor XJ40 has a problem with the charge switch/pressure switch for the brakes. It has a constant hard pulsing unless you disconect the cannon plug going to it. Any ideas other than the $300 plus switches?
I think I would rather play with my 94 XJS conv, but you got to help others.
Thanks for any help, John owlseye
If this helps anyone point me in the right direction, the VCM quit working when the battery was changed out. Before then all was perfect. Now only the speedo,tach, and warning box work, outline only-no icons orprintout.No odometer, oil pressure, volt, temp, fuel, gear selector readout. I have checked all the relays under the right scuttle, all 3 fuse locations to no avail. If I remember correctly the VCMs were vary voltage sensitive and would fail due to voltage spikes. Does my memory fail me?
Also this poor XJ40 has a problem with the charge switch/pressure switch for the brakes. It has a constant hard pulsing unless you disconect the cannon plug going to it. Any ideas other than the $300 plus switches?
I think I would rather play with my 94 XJS conv, but you got to help others.
Thanks for any help, John owlseye
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