[xj-s] Missing Headlamp Relay?

You experts will be getting tired of me soon, but before you do,
can I slip in another dumb question :slight_smile:

I posted a little while back that my ‘headlamp logic module’
appears to be defective - I need to give it a good thwack most
nights to get the headlamps to come on. I’m trying to track down a
replacement, however …

Sean Straw mentioned in reply to a previous post that this logic
thing gets power from the main headlamp relay, fourth relay from
the front on the the little bank of relays under the hood, driver’s
side. However, mine isn’t there. The mounting for it (kind of pinky-
red color) is there, but no relay.

Now the seriously dumb question - does the headlamp logic unit
supercede this relay or is it genuinely missing, and therefore
contributing to my ‘mind of their own’ headlamps?

See, I told you you’ll be getting tired of me soon :)–
'92 XJS V12 Conv. Was a mess, getting less messy
Burbank, CA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

// please trim quoted text to context only

I believe that it was I who mentioned the main headlight relay (4th from the
front) feeding the headlamp logic module. The red socket that you speak of
should be between the 5 relays and the headlamp logic module, and is
normally empty. I’m not sure what it’s for, maybe a diagnostic connector. (I
thought something was missing the first time I saw it, too.) However, you
should still have the 4th relay, unless they moved it between our model
years.

Do you have 5 relays along the left side? If so, they are (from front to
back) aux. fan; parking light; front fog light; headlight; and smog pump. If
any of them are blue (they probably all are), you should replace them. The
old blue relays would often fail due to moisture. The black ones that
superceded them are apparently sealed better. New relays are under $10 each.
At the very least, remove them, burnish the tarnish off, spray plenty of
contact cleaner in the sockets, squirt a little dielectric grease in the
sockets, and pop the relays back in. It’s a good idea to clean the sockets
even if you replace the relays.

Gary
94 4.0L Convertible
San Jose, CA----- Original Message -----

Sean Straw mentioned in reply to a previous post that this logic
thing gets power from the main headlamp relay, fourth relay from
the front on the the little bank of relays under the hood, driver’s
side. However, mine isn’t there. The mounting for it (kind of pinky-
red color) is there, but no relay.

Now the seriously dumb question - does the headlamp logic unit
supercede this relay or is it genuinely missing, and therefore
contributing to my ‘mind of their own’ headlamps?

See, I told you you’ll be getting tired of me soon :slight_smile:

'92 XJS V12 Conv. Was a mess, getting less messy
Burbank, CA, United States

// please trim quoted text to context only

In reply to a message from Gary sent Tue 11 Mar 2003:

Gary, sorry yes, it was you, not Sean, who replied previously -
apologies.

And you’re right, I can’t count. I have the four relays you mention
all intact, with the empty fifth one alongside. The relays are
blue - I’ll replace them as you advise. I did take 'em all out
recently and did the clean & replace, but if they’re going to cause
a problem I may as well get shot of them now.–
The original message included these comments:

I believe that it was I who mentioned the main headlight relay (4th from the
front) feeding the headlamp logic module. The red socket that you speak of
should be between the 5 relays and the headlamp logic module, and is
normally empty. I’m not sure what it’s for, maybe a diagnostic connector. (I


'92 XJS V12 Conv. Was a mess, getting less messy
Burbank, CA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

// please trim quoted text to context only