Hello, I am having an issue with my overhead console burning out a trace on the control board! (2 times so far) This occurred 1-2 days after first changing the dome and map lights. At first I thought maybe I did something wrong with the lights, but after installing new lights and a whole new overhead console it burnt out again… The first time it burnt out it sent the whole system whack parking brake issues, restricted performance threw a few codes as well, bank 1 too lean, Maf sensor high intermittent voltage, bank 2 too lean. I don’t know if these were related to the short, but I cleared those codes after looking at live engine data and determining everything was fine. Now after I installed the new overhead unit it burnt out immediately. This time no issues as I kept the car off however I decided to keep the console plugged in and found that pressing the map lights turned on the dome light dimly (map lights do not turn on), and pressing the dome light turned the back and front lights on but not the dome light. Also, I checked everything else out too. The sunroof button works, garage buttons are working, and the small led is lit. Maybe I installed the wrong bulbs, and I dont know if it matters, but im pretty sure I used the same type of LEDs that were in there before. Could it be that the housing bracket holding the lights is the issue? The bracket is cracked up a little bit. Any help is appreciated, thanks.

 

Also, forgot to mention, I will try to remove the board from the Consol with a soldering iron and repair the burnt out trace. I don’t know when I will have the time or patience for that but I will post an update if I have one.

 

I am not 100% sure, if I get this right - a picture from your end might certainly help.
But I understand that your plastic is melting from the hot bulb. For the bulb to get THAT hot, it has to be brightly lit for quite a time, i.e. the obvious question is: Is the dome light bulb off when it is supposed to be off?
Also: Incandescent bulbs (i.e. "antiquated old style bulbs) are those, which would get that hot. LED bulbs can also get hot, but not THAT hot (the reason for this follows in my next line).

Hence, for that matter (and because incandescent bulbs are swallowing way to much energy (btw.: all that "wasted" energy gets transformed into heat (I hope you can tell that I am an Electrical Engineer;;; ))), you should have swapped all interior bulbs over to LEDs a long time ago, because you will get all kinds of issues when you drain your battery on a Jag.

 

Unfortunately it’s 3am here and I’m comfy in bed so a picture will have to wait for another day once I can get the pcb out and locate the short.

There is no plastic melting, the first time it was a trace that shorted out on the pcb. I don’t know for sure if it was the same spot that burnt out this time, just assuming that it is. As far as I know nothing is overheating and the dome light didn’t even get the chance to turn on this time before the pcb burnt out.

 

OK. I can't remember, if the issue, which I did have with a non-operational Dome light unit was in an X-Type or S-Type, But I think, it was the S-Type:
Anyway: The "electronics" - if you can call it that - in the dome light unit, was buggered, hence, I simply threw it out.
As I am using LED bulbs all over (which do not draw that much current), it is not a problem to let the door ajar-switches "control" the bulbs directly.

By "throwing the dome light unit out" I meant that I simply bypassed the electronics of the dome light unit and connected the incoming 12V directly to the LED bulbs.
Actually, I think the map-reading lights, which are an integral part of the dome light units are imho utterly useless in every car. I connected the dome light bulb AND both reading lights such that they all light up, when the doors open... I think, this might be the solution for your problem as well.

 

Gotcha, I can try bypassing the electronics, but if they are bypassed the overhead light buttons will not work, correct?
Anyways I would still wonder why replacing bulbs would result in a short on the control board two days later then, after installing the new part, instantaneously shorting out again before even turning the lights on... Also, I’m questioning how that short the first time could have affected the parking brake and set off multiple codes & check engine light.

I’ve had lots of strange issues with this jag, most everything else I’ve been able to fix besides this. Although I can’t really complain since it was free

 

It’s okay. We figured that out a long time ago and we don’t hold it against you.

Are the OEM bulbs LED? If originally incandescent, I’m wondering about the quality of the LED replacements. In theory, LED bulbs are superior in many aspects, especially reduced current draw. In practice, the quality of Fling Dung brand LED bulbs can be pretty dismal.

One issue is many automotive applications were originally incandescent. Many circuits have computerized monitoring for a burned out bulb. Typically the computer expects to see a certain range of amp draw when illuminated, and probably a certain range of resistance when off.

Switch to an LED and now those characteristics are way off and messages are generated for a bulb failure. We have seen this multiple times on the forum.

How do LED manufacturers get around this so you will buy their product? They add resistors and diodes and other little electronic magic to mimic the characteristics of an incandescent bulb. You get zero energy savings as the LEDs have to draw the same current as the original incandescents. So even if the LED portion of the replacement draws little current, the rest of the package still draws a lot.

This annoying workaround is something the LED manufacturers don’t advertise. And unfortunately, with all that electronic magic, the overall QC of these LED bulbs can be pretty dismal.

Hold on before you start typing “Thanks Karl, great reasoning on your part, but the interior lighting is not monitored for bulb failure, you mouth-breathing imbecile!” Manufacturers typically include these features on most automotive LEDs, as the same bulbs might be used for other circuits that are monitored.

 

I would be very careful with this approach. The trace that failed was the weak point in the circuit. It failed due to excess current draw, for reasons still unknown. The circuit board acted as an expensive and inconvenient fuse.

Beef up the weak point and something else will fail if the excess current draw is still present. The present failure scenario was basically a nuisance. A failure elsewhere could cause a fire or other serious damage.

 

Rest assured, you are not the first person to experience the parking brake message. Here’s a little light reading to keep you awake at night:


https://www.jaguarforums.com/forum/s...-faults-193787


Specifically, make sure your charging system is within specifications. If overcharging, this may be affecting the interior light circuit that keeps acting up. Overcharging can also damage the battery, conversely leading to low prestart voltage and known electrical problems as detailed at the link above.

Testing the charging system is easy. For any electrical troubleshooting, always begin with a fully charged battery. This is an important prerequisite, so please don’t skip over it. I highly recommend an automatic charger with at least a ten amp output. A trickle charger won’t cut it, so don’t waste your time with one.

With the battery fully charged, measure the voltage at the battery terminals You should see at least 12.6v, which is a very high minimum compared to most cars.

Start the engine and you should see approximately 14.5 volts. After several minutes, it should slowly decrease to around 13.7. This decrease is very important, to prevent cooking the battery.

 

Quote:
Originally Posted by Peter_of_Australia
I hope you can tell that I am an Electrical Engineer…

[QUOTE=kr98664;2786862]It’s okay. We figured that out a long time ago and we don’t hold it against you.

...but I'm a man of mystery and imagination...! If you don't like Electrical Engineers, then I am a Mechanical Engineer for you... - because I am a Mechatronics Engineer...

PS: To be precise: German Masters Degree from the Technical University in Darmstadt & I did my final year project in Sydney, Australia.

 

Im sure the original bulbs were incandescent, but It’s had leds in the car since I got it a year ago. That’s where it confuses me as to why it would short the board now. Perhaps I could have gotten cheap garbage leds but they look the exact same as what I pulled out… regardless my plan now is to repair the pcb and retry with new incandescent bulbs.

 

Battery & charging system are in perfect shape.

 

My money is on the LED bulbs causing the problem.

You can get all kinds of weird faults when fitting them on cars that didn't originally have them.

My STR has LED's fitted and occasionally I get the lamps above the rear doors illuminating slightly when they should be off.

 

Could be the lights. I’m going to take the whole thing apart, repair the board and try again with incandescent bulbs. Hopefully the board dosnt short out somewhere else and catch fire.

 

Reply to an earlier question from Joco: Yes, of course, if you bypass the control units, the switches do not have a function any more. I recalled meanwhile that, yes, I did have a problem on the the S-Type with that dome-light control unit, and the problem was that the switches were buggered up. Hence, the map-lights were non-functional anyway. I connected the overhead dome light and the 2 "map"-light all directly to the incoming 12V and they all light up, when the door opens.
And as the name says: MAP-light...: No one uses paper maps anymore, hence I do not see a use for them anymore anyway.
And considering that the head unit of your gets hot without known reasons: I would not recommend using the control unit (and an attempt to repair will probably fail) and bypass it.

@ Karl:
About your point above that the LED lights cause error messages on the display, because they have less resistance: Yes, sometimes, and sometimes not. I have that error message on my X308 (rear bulb failure), where I have rear LED bulbs. When I find time, I'll try to do something about that (see below).
I replaced (apart from all interior bulbs) also at least the front indicator bulbs with LED (maybe the rear, too, cannot remember), and I did not get an error message, but that probably is, because I installed in the front a high-tech LED indicator bulb, which doubles up as (white) daytime-running light, when the indicator is not in use. So I had never had any problem there to start with. But if I had had one, maybe what I did next to the S-Type would have fixed that issue: I replaced the ugly orange useless reflectors on both sides (front and rear) with clear X-Type front side indicators (modified). This looks so much better, is obviously saver (as EVERYTHING flashes yellow all around, when I set the indicator), and it increased the total resistance WITHOUT use of an additional resistor. - And that I might try on the X308 rear bulbs as well, by adding a red Neon-LED strip at the back somewhere.

 

While I have the board taken apart would installing a fuse somewhere stop the trace from short circuiting? I would much rather keep changing a fuse until I can figure out the issue

 

I agree, repair on the trace would result in another short circuit somewhere else if I don’t find what’s causing it, however my plan is to get oem incandescent bulbs and try again with those after the repair. If it shorts again maybe I can narrow down what’s causing it.
I would like to have the overhead console working… you can call me a stickler if you want

 

Yes, this is an excellent idea. Is there room in the overhead housing for a fuse in there?

 

Im sure I can find somewhere to slip a fuse in, I guess I need to trace down where the affected spot is getting power from and put it there.

 

How big is the circuit board? Could you solder a small glass tube fuse directly across the damaged area? Not super convenient to replace, but good for peace of mind.