1. Home
  2. Automotive Technologies
  3. Clock lights up only at night, 2005 Toyota Solara, can't be seen in the daytime

Clock lights up only at night, 2005 Toyota Solara, can't be seen in the daytime

Addressed especially to Clare and to anyone who thinks he's as smart as Clare is.

Here is the wiring diagram for this car,

formatting link
's an odg file, that LibreOffice Draw creates. I think most people have programs that can display it, or the notes below have almost all the same information.

I made an understandable but mistaken assumption in my first posts about this, so let's forget about them and let me ask the question correctly:

The instruments above my car radio on a 2005 Toyota Solara can't be seen in the daytime, unless the sun shines in directly through the rear window, but they are illuminated when it's dark out. The illumination is fine and they are easy to read.

I want to read them in the daytime too!

The instrument unit includes 1 Trip Monitor (MPG, Avg MPG, DTE, avg MPH, ET) 2 Clock 3 Outdoor Temp Passenger present but seat belt not on - light.

From now on I'll call this whole thing the Clock.

1 and 2 light up with ignition in ACC and ON, 3 lights up in ON, but in all cases, only if it's dark out. This is true when the headlight switch is in the Auto position or any other position such as Parking light, Headlight, or OFF.

What misled me before is that I've observed and the wiring diagram agrees that when it gets dark, a photocell signals the Body ECU which closes the Taillight relay and that sends power to the taillights and the Panel fuse, and the Panel fuse powers lights in the speedometer cluster, radio buttons, AC buttons, seat heater switches, gear shift indicator and the glove box.

I mistakenly assumed that since those lights go on at night, the Clock lights go on for the same reason. But in fact, the Clock lights go on in the dark even if the Panel fuse has been removed, and they don't go on in the daytime even if the Panel fuse has been bypassed to a source that is 12V whenever the car is running, even in the daytime, and when doing that has made all those other lights go on all the time that normally go on only at night.

So am I to believe there are two separate mechanisms for turning on lights at night? Why would they do that, and what would be the other mechanism?

BTW, if I use a dark-colored multi-layer rag to cover the light sensor in the dashboard, I will trick the headlights into going on in the day time. It takes 4 or 5 seconds for them to go on, and then about the same for them to go off when I remove the rag. But doing this doesn't make the Clock lights go on. But night time does make the clock lights go on. What makes the car think it's night if covering the light sensor didn't do that? WHAT ELSE COULD THERE BE?

So I looked in detail at the Clock. It's supplied by 5, count 'em, five, fuses. Pins 7, 15, 16, 17, 22

7 comes from the IGN fuse, 12v when engine running 15 comes from the Panel fuse, 12v when it's dark out 16 comes from the Gauge1 fuse, 12v when ignition sw. is ON 17 comes from the ECU ACC fuse, 12v when key in ACC or ON 22 comes from the Dome fuse, always 12v,

All the pins are described next. Pin 6 seems hard to understand.

Pin 6. TAU terminal on the clock. Goes to Injector No. 1 WHY? Why does it have input from the Injector. To calculate MPG, really? Even though it has input on 5 labeled Fuel and on 12 labeled Speed. So why? Certainly not to tell the clock when it's dark out.

Label Color Conn. Function 1 GND1 W-B 2 TH- B-W IG6 AC ambient temp sensor (near front bumper) 3 TH+ G-R IG6 return from 2 4 SW 1 R Steering wheel display-control, and on to ground 5 FUEL LG-R to speedo cluster, fuel gauge, used for mpg display 6 TAU L IM2 to Injector No. 1 WHY? Why does it have input from the Injector. For MPG? but it has input from 5-Fuel and

12-Speed. 7 TAUB B-R IM2 return from Injector No. 1 and also to IGN FUSE, 12v when engine running 8 TBD L-B airbag sensor, 1 9 TX-1 W-B **but doesn't appy to my car 10 TX-2 W-B same as 1 for some reason 11 PBEW L-R airbag sensor, 2 12 SPD V-W to speedometer, used I'm sure for mpg display 13 DATA G-Y IK1 WHY? to TAM A11(A) A/C Control Assembly. So does TAM mean Temperature AMbient? I guess so, since the AC page shows just this part of the clock including pins 2 and 3 (the ambient temperature sensor), and since the instrument 3 in the list at the top is the outdoor temperature. 14 P-AB V airbag sensor, 3 15 TAIL G to Panel FUSE, but light goes on at night even when Panel fuse is missing, and doesn't go on in day-time, even when Taillight relay is bypassed and Panel Fuse is energized. 16 IG R-L to Gauge1 FUSE, 12v when ign. sw. ON, powers the pass. seat belt warning light and much other stuff, only have 2006 list.) 17 ACC Gr to ECU ACC FUSE, 12v when key in ACC or ON (also headlights, fog light, speedo meter, power mirror, AUTO LIGHT CONTROL) 18 ILL- W-G to speedo cluster (combination meter) 19 TAMO LG-R to skid control ECU. What does this have to do with any of the 3 gauges in the clock? 22 B+ R from Dome FUSE, always 12v, needed to keep clock running all the time (also dome light, fob receiver, garage door opener)

But does any of this show how the lights in the Clock are on at night and not on during the day?

(Part of the reason it's taken so long to ask this question is that some testing can only be done at night and some only int

Reply to
micky
Loading thread data ...

Um. It's a clock. Maybe it just knows what time it is.

Reply to
Scott Lurndal

Its certain that the problem is the programming, not the simple electrical connections. The evidence for that is the delay you see when covering and uncovering the photocell. That proves that it isnt simple electrical connections driving what you see.

Reply to
Rod Speed

Below, I'm assuming what some of the pins do. For example, if it's called Fuel and comes from tghe speedo cluster, I asssume it's coming from the fuel gauge and has to do with computing MPG.

Even so, regardless of what the programming in the body ECU or elsewhere is, where the wires go into the Clock, there has to be something at night that provides power to those lights, or in the daytime, a signal that tells the Clock not to light up.

I'm ready to rewire the car to make up for that.

In the first case, if I could figure out*** what pin provides the power for the light during the night, I could hot wire** it to provide the same power during the day.

In the second case, if I could figure out which pin the signal comes to the Clock to say don't light up, I could cut that wire. At least until I saw what else that disabled. It might be worth it, it might not.

**That's what I tried to do in the first place. I removed the Panel fuse but ran a jumper from the "On-when-runing power to the Seat Heater switch" to the Seat-heater-light. Now all those dash lights in parallel with the seat heater light are on whenever he car is running, not just at night.

I want to do something similar for the Clock, but... Pin 18 goes to terminal Ill-, which stand for Illumination, but it's negative. I guess the possitive is one of those fuses.

Hmm going back to the speedo cluster would make sense if there was a dimmer control on the speedo, and in some of the toyotanation posts about dashlight, they had success by twisting the dimmer knob past the detent. But those cars were a year or two newer, and I don't have a detent. If I twist any harder, I'll break it.

Still, maybe if I "hot"-wire Ill-, pin 18, that is, not making it bot but grounding it, maybe that will bypass something in the speedo part of the dash board. The wire is W-G and goes to the combinaton meter, their word for the speedo cluster. There are in the wiring manual 160 instances of the word "combination". [-(

***I tried taking the Clock apart, but it was just a circuit board with a chip and a few other parts.
Reply to
micky

Makes sense.

I don't remember ignoring that line but I've been busy lately and haven't caught readers here up on a lot of projects in progresss. I hope to do that soon.

Anyhow, the dimmer didn't solve my problem (even though it seemed to solve the opposite problem for people asking questions on the web.

And there is no detent on this dimmer.

BUT WHAT IS REALLY INTERESTING I LEARNED LAST NIGHT. I went out at 2AM to check the car, even though I was sleepy and didn't really want to, because if I didn't, I'd have to have waited until the next night.

So... in the dark, when the taillight relay is bypassed so that the dash lights** are on even in the daytime, and the Clock lights are on (because it's dark) the dimmer controls the brightness of all the lights, every one***

BUT, AND GET THIS BUT, when I remove the jumper wire**** so that the the dash lights** are not lit, then the dimmer control has NO EFFECT on the Clock lights. The lights are at full brightness.

So in a way the Clock lights are independant of the Dash lights, but otoh, they're simultaneously controlled by the same dimmer. That took some work on Toyota's part.

The dimmer wiring isn't shown in the wiring manual -- I don't think the dimmer is shown at all and certainly not individual wires -- but now that the speedometer is out and its back off, I can see a little box

1/2" cube, on the surface of the circuit board, directly behind the dimmer knob. It has a short connector, 1" wires, to the ciruit board with yellow, red, blue, and black wires. I think it might only need 3 wires if Toyota had wired all the lights the same and the fourth might be related to the Clock.

But I don't know which wire is the fourth, and if I did I wouldn't know whether to cut it or to ground it, or what. The circuitry is too confusing to me, since sometimes the dimmer has an effect and sometimes it doesn't. And it's too close to other wiring it could affect. OTOH, if nothing else works I might come back and fool around here.

It is so complicated, and Toyota went to a lot of trouble to make it work this way, when if they'd done nothing and wired the Clock lights the same as the other panel lights, it would have made more sense IMO, not just for me but for anyone. And it would have enabled me to easily hotwire them.

I don't miss not having lights on the other dash lights during the day time, because everything is visible anyhow. The instruments are moving needles, or there are buttons that can't be missed. As to the shift indicator, I rarely look at that. I know where I put the shifter. As to the glove box light, I think it should be illuminated in the day time too, but it's been 30 years since I hunted for something in the glove box. It's only the clock and the mpg/etc. that I want to see, and because they are the only LCD indicators in the car, these are the ones I can't read.

**Speedo, radio, AC, and seat heater buttons, console gear indicator light, and glovebox light.

***(FWIW, the clock lights start to dim a little behind the others but they all get totally dark at the same point, or maybe almost totally dark.)

****The jumper wire goes from one wire to another on a seat heater switch, from 12volts when the car is running to the switch light and from that wire to all the other dash lights. I've removed the Panel fuse that would power all these things, so that the taillight relay is closed has no effect. The power is totally dependant on whether the jumper wire is in position.

Reply to
micky

Now that the speedometer is out, I can silence the annoying**** buzzer.

It sits on top of a circuit board, and I have no access to the other side (because there are 4 needle meters*** mounted to the same pcb whose needles are on shafts that go alll t he way to the other side.

If you were me, or better yet if you were you, would you

a) stuff cloth in the little hole in the piezo buzzer to make the noise lower, hopefully much lower

b) destory the buzzer from the top. (Will this cause trouble.)

c) after it's destroyed, attach wires that go below the dash so if I find I made a big mistake, I can connect another buzzer, at least temporarily.

formatting link

**Speed, tach, gas, coolant temp

The obvious way to avoid this noise is to disconnect the driver's door switch. More than one youtube recommends this. One calls it the perfect way, but it's not. This worked fine when there was more than one switch. I think my LeBaron door had 3 of them. One for the "dome light", one for some buzzer, and one for ???

But because of microprocessors, Toyota decided to get by with one switch.

First problem, unlock the door with the fob, get in the car, a couple minutes later the doors lock and maybe the immobilizer turns on. Because it doesn't know I got in the car, so it resets (That's because of thieves who would drive by sending out unlock codes, but they wouldn't know immediatley which car they unlocked, so if they didn't get there within say 30 seconds, the alarm re-arms.)

Second problem even worse: When I turned off the car, opened the door, used the lock button to lock all the doors, and got out, the alarm probably was set in 30 seconds but nothing turned out the headlights. It didnt' know I had left the car, thought I was sitting inside and just locked the doors. Already left the lights on once for 5 minutes and once for 30!! I can't live like this. (There might also be a 30-minute timer, but who knows if maybe I messed that up too.)

I think there was a 3rd problem, not sure.

So because of these unforeseen problems, I suppose crushing the buzzer might lead to unforeseen problems.

What do you think?

**** The buzzer beeps 4 times whenver I start the car, to remind me to put on the seatbelt. This doesn't bother me much because it's only 4 times, and I suppose it doesn't do that if I've already put the belt on.

But it beeps constantly if the driver's door is open, the engine off, and the key in the ignition. This was intolerable when working on the fusebox, the added switch to open the trunk electically, and opening the speedommeter to fix the Clock light. So I disconnected the switch temporarily, but there are lots of shorter times when I hate this noise.

So I offer choices a, b, or c, above. Which should I do.

Reply to
micky

Still working on this but a temporary report.

Took out the speedometer, but even though there are 64 wires spread over

2 connectors (40 and 24) none of the wires were the right color W-G.

So I had to take out the Clock cluster again.

This time it was a little easier because with the speedometer out, I could get my hand in and behind the clock. Couldn't push more than a bit, but enough to stick a screwdriver in from the top.

Took the clock out, again, because can't see the wiring otherwise.

20 wires and one is the right one, ILL-, W-G, and I will cut it today and see what happens, and try grounding the clock end, maybe through a resistor, and see what happens. Except it will be 93 degrees so may wait until tomorrow.

Last night I came home at dark with no speedometer and no clock and was quite surprised that NONE OF THE DASH/PANEL LIGHTS WERE ON!!! The outside lights worked, inclduing the turn signals, but the 12v that is supposed to be on whenever the engine is running must not have been.

I almost know the wiring diagram by heart now and I find that another curiosity. Taking out the speedo and the clock shoudbn't have caused this but it did. I should have checked the wipers, washer, seat heaters, etc. which are on the same relay. A relay that should have been closed when the ignition is on (even if the car isn't running.) I'll do that tonight.

Reply to
micky

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.