Headlight electrical on 1998 T&C LX

[ASJT3]

Hey guys, (1998 T&C LX)

So from what I hear electrical problems on the T&C are not uncommon. I've got an annoying problem where the headlights will flicker after being on for about 1 min. They flicker so randomly and sometimes at such a high frequency that it seems to almost certainly be a contact failure (and the fact that it happens only after 1 min from a cold startup indicates thermal expansion in the contact joint). Other problems will crop up too such as loss of pwr locks, interior lighting loss, instrument panel loss...I'm hoping these are being caused by the disruption in the headlight switch (before turning on beams and subsequent headlight flickering all systems function normally). Note that the flickering doesn't happen for the parking lamps, only the headlight low-beams and NOT the highbeams! I should also note that drivetrain / driveability is not affected (except at night obviously, when I have no choice other than to rely solely on the highbeams).

Now from what I've heard this could be linked to bad solder joint on the instrument panel (IP). I took off the IP and followed the photo guide referenced elsewhere in this forum; I did not see any cracked solder joints as suggested however I re-flowed some of the connecting pin joints anyway. Unfortunately, problem not solved.

However..... after re-testing I disconnected the IP from the system and the headlight problem still arose, so hopefully that means I can rule out IP solder problems?

My first instinct when this problem first started was that it was a headlight switch problem. I went to the junkyard and pulled a seemingly good shape switch from another vehicle and plopped it in mine. Same problem. So either I am unlucky enough to have stumbled upon ANOTHER faulty switch or I have headlight switch wiring problems?

What I need to further my investigation

In order to rule out a bad headlight switch, I would like to jumper the wires to turn on the headlight/parking lights (whatever wires are activated in the headlight position). Does anyone have a pinout diagram of this switch/plug or know which wires to jumper? (It's the blue-colored plug, the middle of the three plugs for the lower left mirror/headlight/dimmer switch panel.)

Any other recommendations / this problem sounding familiar?

Much appreciated and sorry for the long post,

Alex

[RIP]

Pin #2 is ground. (black wire)
Pin#3 is headlight power from the BCM (light green/orange)
Pin #8 is parking light power from the BCM (white)

Not so sure dancing around power from the BCM is a great idea. Do yourself a favor and disconnect the negative battery cable, set the jumpers then reconnect the battery.

An Alternative is to pull the low beam relay and jumper the output contacts at pins #30 and #87 on the panel socket. Not really bypassing the BCM, just taking away it's control of the relay. Pin #30 is hot all the time so doesn't matter where the switch is. Looks like the high beams aren't controlled by the BCM. May explain why they work fine.

[DerekWhite]

electric car is best option because almost petrol and diesel are finishing line.
SO next generation electric car is best choice no pollution or no side effects.

[RIP]

Originally Posted by DerekWhite

electric car is best option because almost petrol and diesel are finishing line.
SO next generation electric car is best choice no pollution or no side effects.

Should have deleted the post, not just the link due to obvious irrelevance.

[ASJT3]

Originally Posted by RIP

Pin #2 is ground. (black wire)
Pin#3 is headlight power from the BCM (light green/orange)
Pin #8 is parking light power from the BCM (white)

Not so sure dancing around power from the BCM is a great idea. Do yourself a favor and disconnect the negative battery cable, set the jumpers then reconnect the battery.

An Alternative is to pull the low beam relay and jumper the output contacts at pins #30 and #87 on the panel socket. Not really bypassing the BCM, just taking away it's control of the relay. Pin #30 is hot all the time so doesn't matter where the switch is. Looks like the high beams aren't controlled by the BCM. May explain why they work fine.

Thanks for the reply. I'll try both solutions. When I jumper 30-87 I just leave the relay out correct?

Having this problem, I can see from a safety standpoint why they kept the high beams separate!

[RIP]

Yes, leave the relay out. The contact ID numbers are on the bottom of the relay. You'll have to correlate them to the socket contacts on the panel.