Jaguar Repair: Turn signal problem- Series 3 XJ6


Question
QUESTION: I have a 1984 Series 3 XJ6. My left turn signal will not blink despite the correct Jaguar recommended bulbs in place. The left one operates both as a turn signal and as a parking light but  the right bulb will only light as a parking light. Where does  the ground for these bulbs terminate so I can clean it? Also when my operating right turn signal blinks the in-dash hazard indicator light blinks in unison with the green turn signal light. Should it do that? I just replaced the hazard flasher switch in the column. Do you think the connections there might be the problem area.

ANSWER: Hi Barry,

I found that it is impossible to diagnose electrical problem by symptoms. The only way I can diagnose any electrical problem is to pick only ONE of the circuits involved and trace it form "load" (item that is not working correctly) to source (Power supply). And the testing must be done in the failed mode (when it is turned on and not working) I also found that it is best when several circuits are involved (like you have) to pick only ONE and the easiest.

In your case that first is the hazard indicator light. The light is not connected to any power except when the hazard switch is turned ON. So I would start testing that circuit only. (in it's failed mode and on without the hazard switch turned on.) If you don't have a good wiring diagram let me know and I will post one on my web site for you to copy.

90% + of the time when I trace down a problem with several circuits and find the problem with the first circuit I trace, it solves all of the other circuit problems.

No ground problem anywhere on the car can possibly make the hazard warning light come on when the hazard switch is turned off.

Let me know if you need the diagram.

Howard

---------- FOLLOW-UP ----------

QUESTION: Howard
I am writing you again because I noticed there was an error in my first emailed question to you. I missed it when I proofread it. Sorry! To correct my earlier email the turn signals are operating as follows......

   Left side turn signal works as parking light and works as turn signal fine. Although, when it operates in the turn signal mode the dashboard green turn indicator light as well as the hazard flasher dash light blinks in unison. ?? I didn't think that it is suppose to do this.
    Right side turn signal lamp works only as a parking light. It does not operate as a turn signal. When the right signal is switched on, I can here the relay clicking under the dash but no flashing in the bumper mounted lamp or in the dash lights.
   If the flasher relay was bad under the dash would the left side lamp work as it is doing now as a turn signal? Could a bad flasher relay cause the hazard dash lamp to blink in unison.  Would the flasher relay cause the right side lamp not to flash as a turn signal even though the left side works?  
    I believe the bumper mounted lamp unplugs behind the grill and fender somewhere but I cannot seem to locate the juncture. Or does it join further up in the engine compartment. Is the juncture, where it plugs in, behind the headlamp? I am sorry again to take up your time with this light issue but when I read my first email I observed the error in my describing where the problem was. Thank you for your response. Barry

Answer
Barry, all of that don't matter, You will drive yourself crazy trying to diagnosing by symptoms. (if I do this it does that and if I do that it does this and on and on and on. that will drive you crazy#

The ONLY way I can correct an electrical problem is to pick ONLY ONE circuit that is doing wrong and take a 12v test light #WHILE IT IS DOING WRONG# and use the test light starting at the LOAD #Item that is doing wrong# and check the power there and then the next joint heading toward the source #BATTERY). Using your diagram. If you don't have one let me know.

This method has a 100% FIX rate and can not fail !!! And most of the time what ever you find wrong is what is wrong with the rest of the circuits.

IT IS IMPOSSIBLE FOR THE HAZARD WARNING LIGHT TO FLASH WHEN THE TURN SIGNAL IS ON. !!!

look AT YOUR DIAGRAM. THE HAZARD WARNING LIGHT IS NOT CONNECTED IN ANY WAY TO THE TURN SIGNAL CIRCUIT WHEN THE HAZARD SWITCH IS "OFF".