Orson_Yancey
NAXJA Forum User
- Location
- Portsmouth, NH
Oct. 15, 2010
Subject: Side marker lamps wiring is different from 1988 to 1990
Dear Jon (5-90),
Broken Ground in the Front Signal Light Socket
I recently sorted-out and repaired my front signal light problems. On the
right signal light, I had to bend a metal contact to make better contact. On
the left signal light, I put in a new pigtail socket, because the ground
wiring inside the socket was broken.
Pigtails are rare. Of the four local auto parts stores I checked, only one
had Ford pigtails and at a price of $11.00 each. I found some on Ebay. I am
stocking a few.
I think the ground problems are the most common causes of signal light
problems. While I was diagnosing my signal light problems, I was preparing
to change the turn signal/hazard switch in the steering column. I read that
the RENIX era Cherokees have GM Saginaw steering columns. I even purchased
an SPX-Miller tool, C4156, lockplate compressor tool for $100. Certainly,
socket ground problems should be diagnosed and ruled-out before going to the
effort of changing the turn signal/hazard switch in the steering column.
Differences in Side Marker Lamps from 1988 to 1990
My XJ is a 1988. I have a 1988 Electrical Trouble Shooting manual which
contains only the wiring diagrams on 11" x 17" sheets. I purchased a 1990
Service Manual Electrical. The 1990 side marker lamp wiring is more complex.
Page 8J-7, at the bottom right states in boldface type, "With the headlamps
ON, the turn and side marker lamps flash alternately." My 1988 side marker
lamps do not flash.
From looking at the 1990 wiring diagrams, the ground wire of the side marker
lamp is connected back to the power feed to the signal lamp. I guess with
the signal lamp power feed wiring alternating between 0 and 12 volts under
control by the flasher unit, this makes the side marker lamp flash alternate-
ly. Essentially, the ground side of the side marker lamp is going back and
forth between 0 and 12 volts. When the ground side of the side marker lamp
is at 0 volts, current flows (side marker lamp ON) and when the ground side
of the side marker lamp is at 12 volts, no current flows (side marker lamp
OFF.) This is what makes the turn and side marker lamps flash alternately.
I do not have a 1990 XJ to actually look over the wiring and do some
measurements. Do you have any thoughts on this?
Sincerely,
Orson P. Yancey
Subject: Side marker lamps wiring is different from 1988 to 1990
Dear Jon (5-90),
Broken Ground in the Front Signal Light Socket
I recently sorted-out and repaired my front signal light problems. On the
right signal light, I had to bend a metal contact to make better contact. On
the left signal light, I put in a new pigtail socket, because the ground
wiring inside the socket was broken.
Pigtails are rare. Of the four local auto parts stores I checked, only one
had Ford pigtails and at a price of $11.00 each. I found some on Ebay. I am
stocking a few.
I think the ground problems are the most common causes of signal light
problems. While I was diagnosing my signal light problems, I was preparing
to change the turn signal/hazard switch in the steering column. I read that
the RENIX era Cherokees have GM Saginaw steering columns. I even purchased
an SPX-Miller tool, C4156, lockplate compressor tool for $100. Certainly,
socket ground problems should be diagnosed and ruled-out before going to the
effort of changing the turn signal/hazard switch in the steering column.
Differences in Side Marker Lamps from 1988 to 1990
My XJ is a 1988. I have a 1988 Electrical Trouble Shooting manual which
contains only the wiring diagrams on 11" x 17" sheets. I purchased a 1990
Service Manual Electrical. The 1990 side marker lamp wiring is more complex.
Page 8J-7, at the bottom right states in boldface type, "With the headlamps
ON, the turn and side marker lamps flash alternately." My 1988 side marker
lamps do not flash.
From looking at the 1990 wiring diagrams, the ground wire of the side marker
lamp is connected back to the power feed to the signal lamp. I guess with
the signal lamp power feed wiring alternating between 0 and 12 volts under
control by the flasher unit, this makes the side marker lamp flash alternate-
ly. Essentially, the ground side of the side marker lamp is going back and
forth between 0 and 12 volts. When the ground side of the side marker lamp
is at 0 volts, current flows (side marker lamp ON) and when the ground side
of the side marker lamp is at 12 volts, no current flows (side marker lamp
OFF.) This is what makes the turn and side marker lamps flash alternately.
I do not have a 1990 XJ to actually look over the wiring and do some
measurements. Do you have any thoughts on this?
Sincerely,
Orson P. Yancey
