Hello!

I have a ’90 XJ-S and an odd thing just started happening. I turn on the low beams and they do not come on. The dash indicator also stays on. I turn on the high beams and both the low and high beams come on – dash light still stays on.

Fuses are good so I am figuring it must be the headlamp relay (Jaguar HEADLAMP RELAY - C38616-OE). I removed it and soaked in QD Electronic Cleaner since I can’t actually get the bugger apart to deep clean. Replaced and no luck. In a last ditch effort I removed the actual five position light switch, took it apart, and gave it a clean (on a side note – do NOT do this – it is torture getting it back together). Same situation.

Before I order a new relay how confident should I be that this solves the problem?

Thank you!

 

Here is a link to the 90 electrical guide.

JagRepair.com - Jaguar Repair Information Resource

Low beam goes straight through the relay from the switch, so 56B of the relay should have 12volts on it when the low beam is switched on

 

Thanks man! I have that in hand and couldn't really find anything else in the line to check.

 

I would check the relay connections and make sure they all go to the correct place, it is entirely possible someone has been there before and it is wired incorrectly

 

I guess I should have specified that everything was working the other day. This just popped up yesterday. Had to drive home with the high beams on.

 

Check/wiggle/clean the fuse connections/contacts in the headlight fuse box.

Check and clean the headlight grounds.

Maybe both "low beam" filaments of the outboard headlights have burned out? Bit of a stretch that they'd burn out at the same time, but....worth checking?

Cheers
DD

 

Did the following and no luck. Ordered the relay and if it fixed my issues I will post and let people know.

 

If the electrical diagram is correct (my experience with jaguar electrical diagrams it may not be correct) low beam goes directly through the relay so if the contact is damaged that could give you the issue you have. I would be looking at the switch next and double checking all the connectors.

Check for 12 volts at terminal 56 and 56B of the relay with low beam switched on.

 

Here is where I am at!

Last night I received the wrong part.

What I ordered was this: http://www.jagbits.com/mm5/graphics/00000001/c38616.jpg

What I received was this: https://www.terrysjag.com/mm5/graphi...eadlamp-1c.jpg

Now apparently this is supposed to be a modern replacement. The terminals were marked differently but there was a wiring diagram included. I wired it all up and here is the scenario:

With the old relay, turning the low beams on does nothing. The front panel light comes on and stays on. Turning the high beams on turns both the low and high beams on. The switch seems to function and the fact the car knows the low beams don't work (because of the panel light) rules out the switch for the most part. Since turning on the high beams activates both sets of lights this tells me the bulbs are good and that I don't have fuse issues (tested fuses and cleaned all connection points anyway).

With the new relay things get wonkier. I turn on the low beams and nothing happens but the dash light doesn't indicate an error. I turn on the high beams and just the low beams come on.

This leads me to believe one of the following is true:
1) The new relay is not in fact a correct replacement for the old one
2) The new relay is defective
3) The wiring diagram is incorrect

On another note both the attachment points for the relay snapped off the bracket. Looks like I will be removing the bracket, drilling out the stubs of the remaining attachment points, and welding new ones on.

I will keep everyone posted just in case someone else comes across this issue.

 

The pic of the part you received doesn't tell us much. Can you send a pic of the diagram?





Which tells us that the low beam filament of the outboard lamps is lacking either power or ground....or both low beam filaments have burned out



Are you referring to the 'high beam' indicator?



So, to clarify, A) the inboard lamps light up and B) the high beam element of the outboard lamps light up. Correct?



There may be more to the problem, and don't take this as a criticism, but I think we need to get back to fundamentals of the system.

You really have three sets of lights.

The inboard lamps ('high beams') are single filament. The outboard lamps are two lights in one: a low beam filament and a high beam filament. When you switch to "high beam" the voltage to the low beam filament is cut off and voltage to the high beam filament is applied.

The outboard bulbs can't be confirmed as 'good' unless *both* filaments of each bulb have been checked. Have you done so?

You probably have...but I had to ask before we got any deeper into the weeds !

Cheers
DD

 

Ok,

To clarify - on the old relay when I turn on the high I get the inboard filament lit and the outboard high beam filament lit. Nothing when turning the switch to the low beam.

On the new relay low beam switch setting does nothing and turning to high beam on the switch just activates the low beam filament on the outboard.

That should rule out the bulbs themselves being an issue should it not?


Now I don't have the internal schematic of the new relay but here is what was included:




I also know the following from the old relay:

56b - Blue/red wire
56 - Blue wire
56a - blue/white wire
81a red + brown wires
31b red + blue wires

Just as a reminder everything worked perfectly a week ago.

Here is the wiring diagram for the headlight system I am using:




I am thinking of throwing a breaker on the battery and manually wiring each state based on the above diagram and using the breaker to test and make sure everything behaves as it should if the relay were in fact working as planned.

-martin

 

Doug,

I am an idiot. It isn't the relay

The most likely culprit is the switch. I wasn't understanding how the circuits worked and then it "clicked". First the relay wasn't switching between A/B. The reason one relay had high beam configuration and the other had low beam is that the internal rocker switch rests in the last known position until given a charge to change. If the rocker had failed then both position 1 and position 2 of the switch would have yielded the same results (position 0 being off).

The fact that nothing happens in position 1 and position 2 throws the lights in the "current relay state" tells me that at LEAST the switch is bad. Taking a reading off the wires feeding into the relay shows:

1) There is no closed circuit when the switch is in position 1
2) The circuit is closed when the switch in in position 2
3) there is no signal going to the relay switch

Additionally I popped open one of the relays was able to simulate "correct behavior".

There is a chance that changing the switch won't fix an unknown electrical problem operating the position of the relay but at the very least position 1 should close a circuit.

Thanks for sticking in there with me.