This is a hardware problem lol

I would check the switch is should latch for high beam. You could test id manually at the connector from the switch. UB (Blue/Black) is the high beam wire and it is switched to ground to activate the HB.

 

I think the reason the parts people KNOW that they can charge $200 is because people are smashing them all of the time.

I WILL MOVE MINE but on my 1990, for now, it is just hanging out there, under the hood with like 2-3 other relays, over the driver's side wheel well, bumped, knocked - top torn off. Mine has a metal cover and I have knocked the top off, to the sound of a pretty violent spark or two, on more than one occasion. Not a nice feeling or sound. And then, with a metal cover, placing the cover back on is like a trip to the dentist for a root canal, or sumpthin, lol... I dont like it.

I would LOVE to know about a rebuild or some alternative - shoot - just a relocation makes sense for me. Pls continue!

 

You mention the module pulled apart quite effortlessly. Exactly how did you do it? I gave up the idea of rebuilding my H.C.M.s a long time ago b/c they appeared to be a sealed modular unit.

btw, for other members with blinky H.C.M.s, don't you also have problems with your instrument panel lights not working .. ditto for the taillights and parking lights? The ONLY things working on my Superblue are the low-beam headlights and the passenger-side high beam light. It's my understanding that all these circuits pass through the H.C.M.. Funny thing is I had a back-up used H.C.M., and swapping them out I'm still getting the same result .. ugh!

 

You probably just have some bad relays. Only the headlamp power runs through the HCM, and if you have working light on one side or the other, the HCM isn't your problem - it doesn't switch the left and right individually. I'd suggest getting hold of a wiring diagram and a test meter.

 

Thanks .. question is, which relay? I lost my maintenance guide (or whatever it is called in the owner's manual set) which has the diagram of the location of all the relays. There must be one in common for the taillight/side-marker light/instrument panel lights circuits, for when that switch is activated. Not sure though how that would affect the driver's side high beam headlight not working.

 

Nor sure what year your car is, but see here for some electrical diagrams: JagRepair.com - Jaguar Repair Information Resource

 

Thanks, Blade. I see now there are 4 separate fuses for the headlights (left/right and high/low). I'll check the driver's side high beam one now and I bet it turns out it is blown. If so, that problem is solved. I tried re-cleaning the relay for the taillights/side-marker lights/instrument lights) twice last night, after noticing my license plate lights were faintly glowing and the door warning chime going off w/o the key in. That fixed that problem and they are all working again.

 

Joining this conversation as I am also having trouble with my module.

I have re-soldered the PCB connections with some improvement. Currently, the high beams remain on at all times until I switch on the headlights to the second position (fully on). When I switch to parking lights or "off" the high beams will light. When I switch off the car, the high beams relay remains activated and the high beams will drain the battery. So the relays are working, but something is not right. AND, I have switched the module with a known good one from a club member's equivalent car. His does not activate the high beams. So we know it is in the module...

 

Hi Blaerunner thank you for the link to Jag Repair
regards Paul west sussex UK

 

I also repaired mine a few years ago and simply re soldered all if the same places you did. Vibrations and heat cycles damage them. Buying a new one will result in the same thing. Best to just beef up the solder points and live free from issues

 

Hi all I only had my 1995 4lt AJ16 for 2 years and I am gradually sorting out its problems

One being the headlamp control unit I have also written a few notes about how to best do the soldering job someone spoke about replacing the components and this is possible but from my experience is not required but unfortunately there is an Integrated circuit that I have not managed to identify so just wondering if there are any updates to the problems people are having with their headlights Paul south Coast UK

 

I’ve noticed that my headlamps took a while to turn on in the last few months. I would switch the unit on and off several times until they finally turned on. Last night, the regular low beams stopped working, but everything else worked fine. I checked the fuses and then found this post. I just re-sodered my unit, following your instructions exactly. It worked great! I’ve only used a soldering iron a handful of times, so even though I’m a novice, your solution worked perfectly for me. You’ve saved me a lot of money. Thank you so much!