New TN User
Join Date: May 2015
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Thanked 0 Times in 0 Posts
iTrader Score: 0 reviews
I've been researching this more, even getting a subscription to TIS to look at the wiring diagrams and FSM. My clock display is also out anytime the light switch is on anything but "off", regardless of the solar sensor sensing light, but it maintains time perfectly. All window switches, except the driver's master switch, have working backlights. Looking at the "illumination" wiring diagram, every switch backlight negative (including the illum functions of AC displays and sunroof switches) go through the clock. The positive wiring goes through 2 fuses and the taillight relay, then to the Main Body ECU (BCM), except the clock positive goes straight to the BCM . I've checked continuity from clock harness to harness UF1 (rear console box), which would encompass, I think, most other affected items. The only test for the clock in the FSM is to hook battery power to 2 terminals to see if the security indicator lights. Mine does. I don't know if this tests the rest of the clock's internal circuit, specifically the illum circuit. I have battery voltage of 12.XX volts at UF1's red (positive) wire with ignition on, and about 9.5 + volts on UF1's white (negative) wire. The 9.5 volts goes up by ~.05 volts with each DECREASE in dash dimmer step. I tested it at the UF1 because that is the furthest connector from everything else, so I can assume the rest of the circuit gets it, too (I think).
Does anyone know of a way to test the internal illum circuit of the clock? With my Nissan vehicles, the FSM has very specific testing procedures and specs to test electronic circuits for these things. The Toyota manual does not list one (unless the security indicator one actually tests the entire circuitry inside the clock, but I don't know).
Interestingly, the illum circuit for the switch backlights, clock, and AC displays do not include the dimmer switch in the combination meter. I guess the combination meter dimmer goes to the BCM, and the signal is sent from there (which apparently works, because my voltage changes with each step of the dimmer switch). So I'm leaning towards either the clock or the BCM being bad. I just don't know which one, and would rather not spend a bunch of money on the wrong part.
Techstream reports no DTC's.
Any ideas would be greatly appreciated.