On my 1991 XJS, both the tac and speedometer quit at the same time. I removed the cluster and cleaned all the contacts with instrument cleaner and fixed the problem. On a previous posting the respondent suggested redundant grounding. I couldnot find a grounding point on the back of the cluster. I noted a wire on the tac terminal rather than the plastic, and wonder if this is the ground or would there be a better place to attach a ground? Lucus is noted for poor grouding. Thanks!

Submitted by jpbii@yahoo.com on Tue, 05/01/2012 - 04:09

Glad your problem is sorted out too Dan. I've been having a similar problem with my 1999 XJR. I get constant, what I beliveve to be, erroneous error indications. This began with "BRAKE LIGHT FAILURE" notices that made me fear I would be pulled over. I checked all my brake lights. Out of 8 brake lites (including the 4 in the center brake lights), only one was out. I receive "ENGINE FAILSAFE MODE" indications frequently. Never have noticed any difference in performance. My cruise control doesn't operate. I have no idea if my Sport Mode operates when I attempt to engage it. I don't drive it very hard. The gentleman I purchased my XJR from suggested that the brake peddle light switch can cause many false indications. Whenever I turn the car off for a minute and restart the indications disappear... for a while. But they always come back.
I recently purchased a new brake light switch but have yet to install it. My mechanic wants $90.00 for the labor. That's about what I paid for the switch. Is anyone familiar with this issue and know if it could correct my problem?

Submitted by tbirddan@comcast.net on Sun, 04/29/2012 - 14:43

Hi Doug- I believe that it wasa ground problem all along. I installed the redundant ground as you recommended and thankfully, everytning works. Many thanks again for your input. A lot of stress wondering if the tac and speedometer were going to work!! Dan

Submitted by bonnettoboot@e… on Thu, 04/19/2012 - 08:56

LUCAS. like many manufacturers offered a range of components. The buyer selected their choice and that was it. A good example is window switches, up to the series 2 XJ the window switches were fullproof, beautiful chrome switches that could be opened up for cleaning. During the John Egan era, in order to save money a cheaper plastic switch was used, probably tens of thousands were replaced over the years. This was Jaguars' decision not lucas'!

Submitted by tbirddan@comcast.net on Thu, 04/19/2012 - 07:55

Hi Doug- I was hoping to hear from you since you reccommended the redundant ground when I looked for info to replace the tac. I have removed the cluster several times since and the recent problem made me again wonder about Lucus. Do you think all that plastic wiring on the back of the cluster is good engineering? The bar is at the top of the cluster. Next time there is a problem, I will install the additioal ground. Thanks again for your reply. Dan

Submitted by dougdwyer1@com… on Wed, 04/18/2012 - 21:24

The "Lucas" stories, while have some kernel of truth, are wayyyy overblown. Cleaning grounds and un-sealed bullet connectors solves the majority of the ballyhooed Lucas problems.

I buy Lucas components when possible as I generally find them to be high grade. Some of the manually-operated switches---wiper switches, window switches, and the like...are pretty crummy, though.

Just my two cents :-)

It's a little comical when some people complain about a Lucas failure on a new-ish Jag and have it turn out to be a Bosch or Nippondenso item :-)

Cheers
DD

Submitted by dougdwyer1@com… on Wed, 04/18/2012 - 21:18

When you remove the cluster you'll see a metal bar running horizontally....can't remember offhand if it's at the top of the cluster or the bottom. Anyhow.....

Run your redundant ground wire from the metal bar to a *known good* ground point under the dash. You choose the exact spot.

Cheers
DD

Submitted by bonnettoboot@e… on Wed, 04/18/2012 - 17:12

DANIEL, I BOUGHT MY FIRST, A MARK 1 SEDAN, IN GERMANY IN 1964, I DON'TT HINK IVE EVER BEEN WITHOUT AT LEAST ONE SINCE- ALONG WITH VIRTUALLY EVERY BRITISH CAR MADE UP TO THE 90'S. NOT ONLY, i AM SURROUNDED BY THEM EVERY DAY IN EVERY CONDITION. sERIOUSLY THERE WAS NEVERANY PROBLEM WITH LUCAS WIRING OR CONNECTIONS, IN FACT EVERY SCREWED CONNECTOR HAD A SPIDER WASHER ADDED,. THERE WAS NEVER A PROBLEM WITH ANY LUCAS EQUIPMENT UP UNTIL THE LATE SEVENTIES, THERE ARE SO MANY CARS OF THE 50'S 60'S THAT STILL HAVE THE ORIGINAL EQUIPMENT!