Hi again all.
I just got me a new problem....
While driving along today I realized my turn signals where not flashing

When I move the lever to operate the turn signals.... I get the arrows on the instrument panel staying on but not flashing.
They also do not turn off after making the turn.
The hazard lights also are not flashing, and do not even show on the instrument panel.

All the lights are in fact lighting up whether using turn or hazard as they should but they do not flash

I have had a bit of a look under the dash on both sides trying to find the Flasher Unit but can not see it anywhere.

I suspect that it has blown and want to replace it....
Can anyone please tell me where it is located???


Oh scary thought...... I hope this is not yet another module....
The modules in each corner do seem to tick as I switch them on and off.

I have been looking for the standard cylindrical type of flasher unit....
Please please tell me it has a standard flasher unit.

 

Hi Bob,

I'll have to check the '88 electrical schematics tomorrow - I'm off to bed so I can get up for church. On our '93, there is no separate traditional flasher unit. I believe the flashing is handled by the CPU. It is possible your turn signal switch has developed a problem, but it doesn't really sound like a switch problem.

I have the '88 schematics so if no one beats me to it, I'll check them tomorrow to see if they reveal any clues.

Cheers,

Don

 

Thanks Don...... Appreciate it
Goodnight mate

 

ok update.....
They seem to be working again... I think the problem may have been not enough charge in the battery.

I had the battery on charge today as it is stuffed and keeps going flat and now they are working fine....

Makes me question the charging system....
As while I am driving there should be plenty of charge getting to the indicators,
It has never done this before while the battery has been low.
It may warrant further investigation.

 

Bob,

Sounds like you're making progress in your diagnosis. Poor battery charging is a common issue on XJ40s and can often be linked to corrosion on the battery power connections and ground stud connections throughout the car, as well as cold solder joints in the fuseboxes. Below are links to photos I took of the locations of these connections and fuseboxes on our '93, which may be a little different from your car, but most of them should be similar.

Cheers,

Don

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Robert,

Clear the boot and pull the BFM's (bulb fail module), they are probably due a good visual inspection and as Don indicated, the ground's should be cleaned.

Open the modules and examine the solder joints. At the least, you will find heavy corrosion/oxidation where the connector pigtails terminate on the board.

88-89 MY are notorious for problems with the BFM's, especially the rear ones. Even if your symptoms cleared for now, they will be back. There are six relays in each BFM and perhaps one is sticking, causing you're parasitic draw....maybe....guess at this point.

 

Bob,

Rob makes an excellent point about the BFMs - a very common source of problems.

I've just taken a look at the '88 schematics, and it does appear that the turn signal and hazard flashing is handled by the Central Microprocessor or CPU. Both the turn signal indicator switch and hazard lamp switch are connected directly to the CPU, which communicates with all four BFMs. I don't know if the actual "flashing" is done in the CPU or in the BFMs. Rob, do you know?

Some owners have had problems with blocked HVAC drains allowing water condensation to collect in the Climate Control Unit (CCU) and drain down onto the CPU, so it might be worth checking the CPU electrical connectors for corrosion and the CPU case for evidence of water ingress. The CPU is behind the passenger knee bolster / dash underpanel and the glove box. I'm attaching a link to photos identifying the underpanel components on our '93. Your car will be somewhat different - Rob can help.

Another possibility occurs to me: The turn signal switch and hazard ground switch operate by connecting pins on the CPU to logic ground. All the logic grounds in the car wind up grounding to the body at one stud (on our '93 its on the bulkhead in the trunk). It would be worth cleaning that ground stud - all the logic ground wires are Black with a Pink tracer, so that makes it easy to know when you find the logic ground stud.

Since you have trouble with both the turn signals and hazard signals, I doubt that the problem is with either of those switches. If you decide the turn signal switch is bad, I do have photos that show both the replacement process as well as a method of repairing the switch.

Keep us informed!

Cheers,

Don

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I thank you both Don and Rob for your suggestions....
I did in fact attack each and every grounding point I could find when I first got the car.
I had read early on in the posts about the poor grounding and corrosion build up at these points.

And I can not remember who, but someone actually posted the locations for all or at least most places.

As for the charging system, I have no doubt that the battery is kaput...
I can charge it on a nightly basis and it still will not charge any higher than half.
I have known for awhile that the Battery is no good, Just dont at this time have the money spare to fork out for a new one.....
But is is on my to-do list hehehee. Cheapest I have found to suit it is $202.
Not exactly a lot, but still a substantial amount out of my pension

As for the charging system, I am convinced it is still ok.....
If I remove either battery terminal while the car is running.... the motor keeps on purring without any change.... and the volt meter is responding to the different level of input regarding charge.

As for the BFM's...... I can only assume you mean the light modules in each corner, I have not really played with them yet....
The only time I did look at them was when I first got the car and the low beam headlights did not work...... I removed the two front ones and visually checked them over, making sure each solenoid thingy (don't you love the technical jargon) was actuating.... and manually pressing them to make contact to see what each was controlling

 

See my post earlier in this thread. And just because you cleaned the grounds some time ago doesn't mean they haven't corroded again...

XJ40s are very sensitive to low battery voltage, so your symptoms may never improve until you are able to replace the battery. If you have a discount store like Walmart in your area, you may be able to find a battery for closer to U.S. $100. $200 is awfully high!

I'm not sure that just because the engine will run with the battery disconnected that you can be certain that the battery is being properly charged by the car's electrical system....

Yes, the Bulb Failure Modules.

Please keep us informed!

Cheers,

Don

 

Thanks again Don....

Of course I know it takes time to learn all there is to know about these beautiful cars, but I feel I am constantly bothering people with silly little questions and problems...

I have worked on cars, restorations etc for most of my life, but Jags seem so foreign to me.....

I have never come across a car that was so intricate, with separate modules and computers for almost everything...... even to the point of dedicated modules for each light assembly.

For the most part I have always played with the older cars (pre computer / pre injector), they are very basic.... even in top end models.

onto the point at hand.... there is no doubt in my mind that the battery is faulty, whether it be a dead cell or what I do not know....

The main problem I have here is that I live in rural country South Australia....
in a tiny little town that does not even have a department store lol.
So anything to do with parts and accessories must be carried out online or a 3 hour drive @ state speed limit into the nearest city.

The battery I mentioned was from K-Mart.... the only one that matched the specific battery required for my car.
I am not able to just use any high cranking amp battery as the battery tray under the hood will not allow for the height of a standard battery. (a bit of an oversight by Jag I think)

Funny thing about it.... the car really needs bugger all power to start her.....
even when the battery is low, as long as she can crank over even only just, she usually starts...
If not I put the old battery charger on the battery for half hour or so and she lives again.
The one time I had the problem with the indicators and hazards..... the battery was almost totally flat.

I do of course realize I am going to continually have charging problems with it until I do eventually replace it lol.

I reckon I might just bite the bullet and go and buy one tomorrow.... well at least lay-by it hehehehe.

 

Just a short note here. I was able to stop the intermittent bulb warnings by cleaning the relay contacts inside of the rear light modules. I used a flat diamond burnishing tool that I have had for years, Radio Shack I think. Could also use 1000 grit abrasive paper folded over. Gently hold the relay closed with the burnishing tool or folded grit paper in between. A few short strokes will clean both faces simultaneously. Greg