1991 xjs Suddenly Stopped

I found the problem everyone.
When the car was imported from the US to Canada in 2001 it was required to have daytime running lights. So the Jaguar Dealer in Dartmouth Nova Scotia installed a wire from the light switch over to the ignition switch. The only way you could start the car is to turn on the headlights and then power would be sent to the ignition allowing the car to start.
To complicate matters there was an inline fuse installed along this wire and then jammed up under the dash.
I thought there must be something up there so I removed the plastic cover beneath the steering wheel, removed the light switch turned my body so my head was stuck up under the dash and my feet we over the front seat and low and behold I found the wire with the fuse inline, replaced the fuse and installed a better inline fuse device and it started the best it has for a long time.
I put some extra wire on the connection and now it sits right above the main fuse panel under the dash so it's clearly visible.
I want to thank everyone for their advice I certainly appreciated all of your comments.

Brian

A brief update after some off-lists chats with Brian.

His XJ-S needed a DRL Module installed to meet Canadian law requirements. It seems as if the "mechanic" did Not install a DRL module, but inside may have just wired the lights directly to the ignition switch.

The extra current demand burned out the ignition switch contacts.

Brian and I had a very pleasant and informative conversation about his Jaguar's electrical problem off-list.

He lives in New Brunswick, CA, and his XJ-S was imported from the USA about 2-3 years ago. It had to have a "Daytime Running Lights" module installed to met CA law. Whomever installed the module messed up badly. I suspect they used the weak ignition switches to directly power the DRL headlights thereby leading to Brian's problem.

Brian could not perform the simple test I asked him to do because he does not yet own a voltmeter. I gave him a source for an inexpensive one.

He really needs somebody with Lucas experience, who lives near him, to help him trace the wiring problems.

Would someone please help him in person. I shall provide whatever information I have to assist.

Hi Don, no I have not found the issue with the conv. yet, and I am poor when it comes to wiring diagrams,,,,,,. Art.........silver007shaw.ca

Brian,

I suggested that you test for voltage at any Solid White Wire because they are the main power feed from the ignition switch. Like JIm, I suspect you have had an ignition switch related failure. My test would have proven or disproven it in one simple step.

Had you followed my suggestion last week, we'd probably have your Jag back on the road already.

I agree with Art's idea - you need to let us know where you are located (city area, not exact home address). You really need to find a nearby fellow XJ-S owner who can help you in person. I will it if you are near enough to me.

It would also be beneficial to those of us trying to help you if you told us what engine you have - V12, AJ6, V8 lump, etc.. Each has it own unique wiring system.

An aside to Art; did you resolve the ABS issue? I found my schematics for it.

Hi Brian,
where do you live , perhaps I know someone in your area that can take a hands on for you,PH # etc, Art

Sorry for the delay Don I am planning to try it tonight. I did put the car in neutral and try but still nothing. I will try to test one of the white wires under the hood.
As for being members of the club I just acquired the car from my son and have no problem contributing the cause however, my first concern is getting the car up and running. I am new to the forum and a new jaguar owner.

Threads like this become part of a knowledge base and are valuable, even when they contain inaccuracies, regardless of the poster.

> Personally I believe persons on this site should have to be members of JCNA

I always hope that our time and experiences that we share freely to help them will encourage them to join one of our affiliate groups.

My participation in our club activities provides my Jaguar "Fix" during snowy winter months.

Personally I believe persons on this site should have to be members of JCNA,
Art

> Checked the terminal on the firewall and it 's fine.

Which of the four terminals on the firewall? Also, four terminals under the hood or four terminals under the dash? Did you have +12 volts?

> We were looking at the relay under the plastic cover ...
Which of dozens of relays under which of several covers?

> Is there anyway to check the relay?
See above! Which Relay? Which cover?

> Don I haven't checked the voltage on the white wires yet but will try that tonight. [Brian wrote that last friday]
Well, you didn't bother to do that did you Brian?

At this point I'm suspecting you are not for real. You never mentioned what engine we are talking about; i.e.,V12, AJ6 or V8 lump.

Many serious, experienced, well-meaning Jaguar onwers here and on the other lists you've visited have offered excellent tests for you to try.

You, however, provide very limited detail and do not follow up on, or address our suggestions.

Have you ever used the web name of "christky" on Jaguar websites before?

Brian

I don't recall what else wasn't working as my main concern was starting. Like you I had full headlights and no clicking at the ignition. The relay has nine spade terminals in it so lots of stuff goes through there. Kirby Palm's book says you can play around cleaning the terminals and moisture can be a problem and Jag schematics are unreliable or wrong. "To test take the relay out of the car and apply power between the W1 and W2 terminals using a jumper from a car battery ( or 9V pushed down on the terminals). You should get a click. Then connect an Ohmeter between C1 and C2 and check that the circuit closes when the relay is energised. Random results between 1 and 25 ohms". He concludes by saying none of this stuff will last, and "Just replace the stinkin relay". Jag P/N C 36611.

By the way my car is an '87 XJ-SC 12 cyl. I don't know what the six cyl set up is.

Still waiting for the results of the test I asked you to try Brian.

I mean the key-fob remote alarm (anti-theft). The reason I ask is it will cut out power to at least some of the circuits (I don't know the inventory - maybe all of them) you're indicating as symptomatic.

Do you mean the door alarm Jim? Yes when the key is in the ignition the alarm goes when the door is opened.

David,

When your problem occurred did you lose all power at the iginition switch for items such as wiper, windows etc?

I have lots of power at the firewall from the battery and have headlights, emergency lights and interior but little else. Does the starter relay control the power of just the starter?

One other thought... (dangerous assumption time) assuming it IS the ignition switch:
Turn on the wipers (or some other failed system)
Turn the key to position 2 (run)
Jiggle the key

Since your car was hot wired somewhere for some reason - maybe a failing ignition switch - try it with the lights on too.

Also, a question: Does the alarm system appear to function?

The fuse panel in the passenger footwell/underdash panel has a bunch of relevant fuses. Try rooting through there.

A note on testing relays. It's pretty easy to verify the function of a relay. It'll take a meter to check for continuity (zero ohms resistance) and a battery (9v should be just fine for checking them). Sometimes they're diagrammed on the top as to which pins are switched and which pins activate the relay. Otherwise you're likely going to have to search the tubes of the internet with the part number . The good news is that you're not going to hurt the relay any by attaching power to the wrong leads.

The fuse panel in the passenger footwell/underdash panel has a bunch of relevant fuses. Try rooting through there.

A note on testing relays. It's pretty easy to verify the function of a relay. It'll take a meter to check for continuity (zero ohms resistance) and a battery (9v should be just fine for checking them). Sometimes they're diagrammed on the top as to which pins are switched and which pins activate the relay. Otherwise you're likely going to have to search the tubes of the internet with the part number . The good news is that you're not going to hurt the relay any by attaching power to the wrong leads.

Hmmm....

Well, you've ruled out the battery.
Three things I would check next:
1) The fuel shutoff collision sensor - though that would still allow the engine to crank. It's worth resetting it anyway because it's easy. Passenger door pillar, just inside. It'll be a box with a hole in the top. Press the rubber covered switch inside the hole to reset.

2) Neutral Safety Switch - it's actually called the Rotary Switch in your shop manual. IT should work in both Park and Neutral. Try starting the car in Neutral. This shouldn't cause the car to actually stop running but it's easy to check.

3) Ignition switch - this seems like the most likely. I had not heard about checking the white wires but that sounds as good as anything. As a suggested test procedure, hook a meter to your starter and verify that it's not receiving power when you try to start it. If it IS then your starter needs replacement. Check the function of the Radio. If there's no power to the radio when the switch is in position 2 then and no power to the starter in position 3 then the ignition switch is suspect.

4) Fuses - there's an aweful lot of fuse panels in that car. I would pull each fuse and check.

Checked the terminal on the firewall and it 's fine.

We were looking at the relay under the plastic cover and wondered if it may be the cause of the problem.

Just doesn't seem to be power from the ignition switch going to the rest of the car. As I said earlier I have headlights, emergency lights and interior door lights but no roof power, window power and or fan, wipers etc.

I appreciate all your comments. Is there anyway to check the relay?

Don I haven't checked the voltage on the white wires yet but will try that tonight.

I've had this problem twice, (103,000 mi) except never while running, but the same symptoms when going to start. Easy fix is the sarter relay located by the top right side of the firewall under a plastic cover. Lucas part marked with 22 RA, 33356B 4800. About $50 at the dealer, I carry a spare.

With the ignition key in the Run position, check for +12 volts at any solid white wire under the hood/bonnet.

> In this car I have to turn the lights on first then start the car.

That is not good. Someone has badly messed up the electrical system. Their previous changes may have created the situation that led to the failure you are having now.

Thanks Art
I have some more information and will check the terminal. I have power from the battery to the firewall. I have headlights, interior lights and emergency lights.
I don't have , (when the iginition is in the on position) any power to wipers, power windows, roof, (its a convertible) or anything else.
I'ts funny that the car just stopped when I was rounding a corner. Its almost like a relay or fuse has failed that provides power from the iginition switch to the rest of the circuits without power that I have mentioned above.
We're still working on it but right now it's a mystery.

Hi Brian,
on the outer firewall,directly above the starter motor,there is a terminal usually under a rubber boot. The nut may have become less than tight and may need tightening.it is located just behind the rhs cam cover area. This is the main starter power feed ( thick wire).

No the engince does not even click when the key is turned on. Thats what is strange. I seem to have lots of power, headlights etc but none at the iginition switch.
In this car I have to turn the lights on first then start the car.

It just suddenly stopped while driving. I even tried to boost it with my other car but still nothing.

does the engine turn over, Art

Thanks guys for the adivice. I have a new battery in the car and have lots of headlights, interior lights etc. It just seems that no power is going from the iginition to start the beast.

Well, the good news is it was running when it quit.
1) Check the battery water level. The plates should be well submerged. Use only distilled water to reflood the battery.

2) Put the battery on a charger for a day. When you jump a dead battery it's a big sink-hole for the charge from the jump vehicle. Put it on a charger for a day then let it sit for an hour. Check the voltage. The voltage on a good battery will be close to 13v. If it's less than 12v it's completely toast.
- of course replace a defunct battery and see if that gets the car to go.

3) Check the fuses. There's a charging system fuse that can knock out the alternator from the running circuit causing the car to run only on battery power.

4) Check the alternator. A dead battery can just be an old battery or it can be killed by an alternator that's not working. The easy check for this is to check the voltage at the battery. It should jump to approximately 14v after the car is started. That indicates the alternator is producing some power. To check the output current you'll need to pull the alternator and take it to a pep-boys or similar for diagnosis. Some clamp-on amp meters can read DC current. If you've got access to one you should be able to clamp over the positive terminal on the alternator and sense operating current. This will vary with load so also turn the fan on full blast, turn on the lights and high beams and you should see some significant current flow out of the alternator.

Based on what you're telling me that's where I would start. Sounds like you've got fuel and air but your electrical system is acting up. Of course, verify that there's fuel and the air filter is clear.

I had driven the car about 35 km at speeds of a little over 100km/hr. It was a humid day , (about 29celcius 90F).
The operating temp was at normal when the car quit and when the car cooled down it still didn't and doesn't start. I almost seems as though little power is getting through when the iginition is turned on. It won't even crank over and when I attempted to boost it again nothing.

> ... I lost power and the car rolled to a stop....

Was the engine at or near operating temperature when it quit?

Did it restart as normal after it cooled down again?

If so, the CPS or the RPM sensor may have failed. They become heat sensitive as they age.

They should each have about 700 ohms resistance when at operating temperature.