Electrical issues

X300
1

Not sure if this is the right place for posting this but, I need help.

97 Jaguar XJ6, Runs amazingly, well, except for the fact that it isn’t starting…So I’ve done a LOT of looking and couldn’t really find anything that solves it, but I tried a TON.

Works: Dashboard lights, maplights, seats, radio, sunroof, power locks… and not sure what else…

Doesn’t Work: headlights, highbeams, starter(as in, doesn’t crank), dome lights(with that weird center button) windshield wipers, will not shift out of park.

Theories: some sort of disconnected wire I can’t find, some sort of security “feature”, a relay or someodd item that isn’t working which I can’t seem to find.

Searched all fuses, switched around all the relays to check for an outed one. Disconnected battery for over 12 hours, ensured battery was charged, tried the security reset thing(use key to lock and unlock the doors numerous times then letting it sit in run for 5-7 minutes), tried to trick the security by rolling down windows locking doors, and opening it, then sitting in and trying to start it. I cried for a bit but I don’t think it helped the car at all.

2

After some extensive research, I’m boiling it down to BCM, expensive way to figure it out. Gosh Darn.

3

did another bcm fix your no start issue? I have that too.

4

I haven’t received it. I ordered it today, should be here on the third. I don’t know how it would have went bad from changing fuel pump but all research and trial points to the bcm.

5

Out of curiosity, what symptoms are you experiencing?

6

I just purchased my 1995 xj6 and it sat for three years because the owner said the “starter was bad”. Towed it to the shop and used a new battery but no crank. Other dashboard stuff lights up but wont crank. our mechanic jumped 12 volt from battery to a pin on a plug under the hood and viola cranked right up. So we know its something electrical. I really haven’t messed with it more than that.

7

You should check the “through the firewall” connection from the battery as this is a crap designed brass stud/steel nut and it corrodes/oxidizes and screws the voltage/amps to the engine compartment up.The connection is up under the dash beside the tunnel and close to the engine in the engine bay.

Regards David

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9

Great info I’ll definitely clean that up first. Thanks nododge!

10

There is a switch in the shifter mechanism that prevents starting in anything other than Park and Neutral. If that switch is bad it prevents the starter relay from working and the car will not start. As a work-around you can jumper across the starter relay.

11

So, bcu didn’t work. Fail. Firewall rcable is fine. I hate my life.

Gosh dang, anyone in northern az? think va has grants for automotive repair? Gosh

12

1650 for the car, 260 for registration, so far about 400 in parts… I’m so depressed, I got the car for my new job as it’s a driving job… this is a fricken nightmare and it’s such a lovely car.

Ok, enough pity-party. So, more diagnostic issues, it won’t shift out of park, could that be a result from when I put it into neutral and pushed it 10 some odd feet before stopping and putting it back into park?

Secondarily, I checked the relays the best I could, but I noticed today my OBIE(whatever it’s called) computer didn’t get power from the connector, so I rearranged the relays again and noticed I got it back, meaning there’s a relay issue for sure, right? I just don’t know how to check them, and there are 14 of them so replacing them all would be a lot of spending on my already strained budget.

I’ve read recommendations and heard them from people I know that you can switch it to run and bypass the starter solenoid, Seems a bit shotty and I don’t want to further ruin my electrics, but I tried it, and now, again, my computer isn’t getting power from the connector meaning that I probably fried the relay or a fuse, checked the ones in the bonnet and boot, haven’t checked the back seat ones… Not sure what else I can try.

Oh, and as per previously mentioned, I did replace the BCU, I had a spare, then ordered a “new” one. The one ordered was a AA not a BB one, but I assume(maybe incorrectly) that they are somewhat interchangable being that the AA one comes standard until it got superceeded by the BB?

Any thoughts or recommendations? I apologize for my whining, just a bit overwhelmed with life, and I am frustrated.

13

I haven’t been following this thread too closely, BUT at this point my advice would be: keep an accurate log of everything you try/do and if it makes no difference put things back as they were when you started. This avoids it becoming a “Bggrs Muddle” and allows logical diagnostics re. root cause and effect.
Above all don’t just throw money at it, there is plenty of expertise and many good brains on J-L and in many cases a solution is eventually found!

Good luck and stay positive and feed it back chapter & verse to the Forum.

14

You should check that when you depress the brake pedal the switch is working as this is the ‘signal’ to pull the lock off the shifter so you can move it into rev/drive etc. (ignition on)

Regards David

15

Have you identified which relay is the starter relay? There should be a map or diagram in the owners handbook. If not, search the internet for a wiring diagram AKA Electrical Guide for your model. That guide is gold so save it to your computer. You may have to buy it, but its worth it.

Pull out the starter relay and identify which pins are #30, #87 and #87A. Identify which are the corresponding tab sockets 30 & 87 in the relay/fuse box. Strip the ends of a piece of wire and touch it to those two sockets. The starter should turn. If it doesn’t, try sockets 30 and 87A. If the key is on the car should start. Let us know what you find.

Socket 30 should have 12V power on it, so you can check it with a test light bulb, touch one wire to socket 30 and the other to any metal part on the car.

Not being able to shift out of Park with the key on could be:

  1. you have to step on the brake pedal
  2. there is a gearshift interlock solenoid that actually stops the shifter, and a gearshift interlock relay that operates this solenoid. Both have fuses to protect them, and relays can get worn out.
    Let us know what you find.
16

For most of the Electrical Guides and other TSB’s Manuals check: www.jagrepair.com

17

Thanks for the feedback! Monday I will be able to test, away on business
right now.

18

Ok, so, new relays, new bcu, no dice, started at ground zero, took tank out
undid and redid all the wires, and suddenly it works. :I what this means is
that i didnt have the trunk of cables fully put in. Dispite rechecking it
numerous times. I am a newb