Photocell

[Don Hudd]

I did this test (thanks to Mc_reatta) that was posted on the icp not readable post:

Enter diagnostics mode

go to BCM override test BS02

vary value from 0 to 99: display should get brighter as value increases

if the value won't change, your BCM is bad

if the display does not get brighter as the value increases, your IPC is bad

if that test works properly,

go to BCM Data BD44 (photocell output)

in bright sunlight or strong light on base of windshield the reading should be 30 or less

cover photocell with heavy opaque material

reading should indicate 90 or more

if not check voltage at the BCM input pin 3D8 and ground.

should read 2 volts or less in bright light, 4 volts or more with opaque covering

If not then photocell is bad, if yes then BCM is bad.<!-- google_ad_section_end -->

I got a reading of a low of 28 and high with light to cell of 49 (used a flashlight shining on cell as I did this when dark outside). I did not do the volt test as I do not know for sure where the bcm is or what input pin 3D8 is. Do I hace a bad photocell? Dash pod lights do not light and crt does not dim in daylight. I did the bcm override test bs02 and display dimmed on decrease and brighter on increase. long post I know but wanted you to know what I did.

Thank you,

Don

[Guest Mc_Reatta]

Photocell is probably defective. You are not getting a value high enough to enter night mode for the BCM to turn on the panel lights.

[DAVES89]

Ronnies site has sources for photocell as well as removal instructions...

[harry yarnell]

I've got good used cells for $9 post paid.

hyarnell1@earthlink.net

[Don Hudd]

Thanks guys

[Don Hudd]

I got the photocell today from Harry, Thanks Harry. Also changed the inverter I got from Jimm Finn, Thanks to Jim also. My dash lights and crt now dim with the dimmer switch, but alas, no pod lights or center console lights. Any ideas? I read on Ronnies site about wd-40 on the pods, tried it, no luck. Is the only answer bad pods or pods? Would just a bad headlight pod keep the wiper pod from lighting?

Thanks,

Don

[Guest Mc_Reatta]

Look at photocell output value in the BCM Data (BD44) in diagnostic mode. Is the value with the cell blacked out over 74 ?

Last time you only got a 49.

[Don Hudd]

yes went up to 90+

[DAVES89]

What I would do is thake the pods apart and look at the illuminescent panel. They are realitively easy to take apart and there are no parts that will blow out and get lost [like on the 90/91]. If the illuminescent panels are cracked it will not light.

Same thing [if the illuminescent panel is cracked] for the console lights.

[Guest Mc_Reatta]

Sounds like it could be your BCM then. BCM knows that the lights are turned on from the pod switch. It then makes sure it's dark out (photocell output over 74) then supplies voltage to the inverters to turn on the pod backlights. If there is a way, you should check the voltage to the inverters and see if there is DC voltage coming in to rule the inverters and luminescent panels out. Input voltage would be dependent on the position of the slide dimmer control in the headlight pod as would the AC output of the inverter. If there is voltage there, then the BCM is OK if not, try to jumper 12 v to the inverter input and see if the panels light up.

[Don Hudd]

I will try that, but could a bad switch be the culprit? Would the headlight switch if bad keep the wiper switch from lighying, and can any of this have to do with the concole lights not lighting. I have changed both inverters with ones I got for Jim Finn last year.

[Guest Mc_Reatta]

If you can dim the instrument lights with the slider on the light switch pod with the parking lights and or headlights on and it being dark then the switch is working with the BCM. If you can't dim them with the lights on that way, see if they dim if you turn that switch off but turn on the fog lights. If that works but the other doesn't then I would suspect the headlight switch. The BCM turns on the luminescent panels by turning on the inverters after it gets the head or parking lights on input and it knows its dark out via the photocell. The luminescent panels in the two switch pods, the shift lever display and the window and mirror switches. The fact that none of them work seems to indicate that the inverters are not being turned on. Could be a BCM issue or another wiring problem.

[Don Hudd]

Thanks for all the help, just went out to try what Mc said and all is working, must not have been dark enough when I tried before, but both dash pads and window switch light up now, not the shifter though but I am happy. Thank you all so very much. This by FAR is the best forum going because of you all

Don

[DAVES89]

Are you getting "The Show" or have you not gotten to the switch in the door?

[Don Hudd]

Dave, no show yet but have not gotten to switch in the door. Had the panel off the other day, could not see how to get to the handle, will check on Ronnies site to see if some help there, Thanks for asking.

Don

[Guest Mc_Reatta]

Don, Use the diagnostic tests I gave you earlier to see if the switches in the door are working or not before you go trying to get to them. Will save you time and skinned knuckles. You still have some wiring issues if your door light isn't working yet.

[Don Hudd]

MC_Reatta, I did the test again, b103 ok, b105 &106 HI when door is opened or handle lifted. But when I start and put in gear with the door ajar, the warning comes on the srt screen. While here, on my tread about drivers door light not working, you asked if power door lock switch worked, I stated yes, but today works when door closed but not when opened, I am going to that tread and update there in case someone is following that thread.

Thanks for your help.

Don

[Guest Mc_Reatta]

Door ajar switch is the only one working as far as the BCM is concerned. You still have wiring issues or a bad BCM.

The courtesy lights come on when you open the driver's door correct? Yet you don't get B105 showing LO when the door is open. :confused:

Door lock switch works when door is closed but not when open. Power to that switch and the door light are direct wired only passing thru a few connectors and splices. If it drops out with the door open it sounds like a broken orange wire where it passes from the door to the jamb.

[Don Hudd]

MC, Sorry I missed typed B103 & 105 ok 106 only stays on HI when lifting door handle. To check for broken wire where passes thru from door to jam, does the rubber covering just pull back from door or jamb?

Thank you so much for all your help. By b106 not working, I assume I need to change the door handle switch?

[Guest Mc_Reatta]

When you get the door panel off again, you can check both the switch and the wiring as there is a connector you can access. That will point you in the right direction.

Hope you have small hands, the door handle is no fun to get to.

Not sure how you get the rubber loose, probably easier to work from the door side since you can get to both sides.

[Don Hudd]

Thank you again, you have been a godsend to me on this car, that was going to be my next question as to the door handle switch, I tried to look in the FSM and hope it is the 1 that just plugs in, I well search the forum and see if anyone has done this before and posted it, I will follow up on this post as well as my "I know your tried of this "post if anyone is following.

[Guest Mc_Reatta]

Both the handle switch and the ajar switch have a white two conductor connector near the end of the black hard plastic wiring channel that runs from the lower inside area of the door up and then back toward the latch end of the door for the connectors you just need to open the rear portion of the channel. You push up from the bottom to raise the hook and pull the lower end of the front where the clips are to pop the front loose and it then hinges up to gain access.

Will check the wire colors for the connectors so you can tell which one belongs to which switch. They are opposite genders, so you can't hook them back the wrong way.

You want to check the continuity of the switches with the ohmmeter and make sure the switch opens and closes electrically, then use the voltmeter to check one of the wires going into the mating connector has 12v, and the other is a ground.

[Don Hudd]

Thanks MC, I assume you are talking about the channel that runs on the door itself. If bad then must disconnect from door latch? Does it just plug in ?

[Guest Mc_Reatta]

Switch is held to the door handle buy a screw. Wires run to the inside of the door where they just plug into the waiting connector.

I imagine you have to remove the door handle from the door in order to get to the switch. Again, if like other cars I've worked on, that's probably 2 nuts on studs holding it in place plus the actuator rods that connect to the latch. None of it is any fun because there's no room and lots of sharp metal edges to cut your hands.

Hope someone can tell you an easier way, but I've looked at mine and figured my show can wait for a while. Changing out the window motors is enough fun for me.

[Guest Mike_s]

The following post is from many years ago, it lists the photo cell as gm part # 25673037 which as of today appears still available for apx $30 from gmparts direct. Ronnie you might consider adding this pt # to your web site

"sensor part # 25673037, mine was $35<BR>The sensor is a small blue plastic thing under the defroster grill. Before you purchase a new one just unplug the old one and turn on the headlights, if dash lights work like they're supposed to then your sensor is faulty, (remember to slide the dash dimmer switch to "dim" or at least "kinda dim"). A completely missing sensor defaults the system to thinking it's dark outside. Also read posts on removing defroster grill, breaks easily and scars up your dash"

[Ronnie]

Thanks Mike for the number. I have added it to the list.

[Don Hudd]

Ok, here is an update. Drivers door light still not working but as to power to the power lock switch, not power if inside curtsey lights are on, if door jamb plunger is push in then have power to it or if door is left open long enough for the lights to go out, have power to lock switch. I thought maybe door jamb switch was bad so swapped with the passenger side, same thing, passenger side works fine. Not a big deal but is puzzeling.

[Guest ReattaFan1]

Im having problems with the panel lights not coming on. Also, I cant get the dimmer switch to function. Both the ICP and the CRT stay bright, their not affected with the light switch or the dimmer pot. I get the exterior head and running lights to come on. The running lights do automatically turn on in the dark. I did test the center console inverter and that one works for sure. Getting to the other dash inverter looks like a nightmare. In the BCM diagnostics mode I get the value to change on the dimming pot (BD42) so thats fine. But the daylight sensor (BD44) I get 9 in bright light. Covering the sensor I get a max of 22 and thats in pitch dark. I'll see if what I come up with doing this test posted here to find out if its my BCM, ICP or just a continuity problem. But Im curious, If I find it to be the sensor will overriding the daylight sensor on page BS03 and setting it at 75% will this get my panel lights to function? Just temporarily until I get a new sensor.

Edited December 19, 2010 by ReattaFan1 (see edit history)

[DAVES89]

It's the photocell in the middle of the dash that is bad. Barney says you can get a replacement from Home Depot. I have never tried that.

Ronnie has great instructions for the removal at his website.

[Guest ReattaFan1]

I'll see if what I come up with doing this test posted here to find out if its my BCM, ICP or just a continuity problem. But Im curious, If I find it to be the sensor will overriding the daylight sensor on page BS03 and setting it at 75% will this get my panel lights to function? Just temporarily until I get a new sensor.

The suspense was killing me so I just ran out to test it. In the BCM service override menu BS02 changing the value did dim and brighten the ICP and the CRT display. Changing BS03 the value did bring up the incandescent light on the center console but dash lights around the speedo cluster (lights,cruise,and wiper) didn't light. So Im also assuming the upper dash inverter is bad as well. Im guessing the main problem is either a continuity issue or the photo sensor is bad. Im excited to get this far. I was hoping that I would be able to keep the dash lights on after the override. I found once you back out of the override service mode it goes back to normal and the lights go back out.

Edited December 19, 2010 by ReattaFan1 (see edit history)

[DAVES89]

This is what I did before I went in my dash after the inverter, but you have to get the "Show". If you get the "show" and your headlight and wiper pods don't light up, it's also the inverter. Mine would light up during the "show" so I knew it was the photocell.

When you replace the photocell it is also a good time to get the inverter loose and work it to the bottom of the dash. This saves you from having to go back in thru the top to get to the inverter when it does fail. [Less risk of breaking the dash in the future].

[Guest ReattaFan1]

Thanks!!! I couldn't find Barney's website so I sent him a request for the link. Thanks for the inverter tip. I'd hate to crack my dash. Ive seen pics on the web where someone annihilated their dash to get through the top.

[padgett]

You can reach the inverter going up from the bottom but use an ace bandage around your arm first or it will come out looking like the loser in a cat fight. Lots of sharp edges.

Takes patience but if concerned about the dash pad, it will work.

[Guest rusty108]

I JUST ORDERED ONE FROM HARRY YARNELL.

$10 POST PAID. SHOULD TAKE BOUT A WEEK TO GET IT USPS.

I`LL LET U KNOW HOW IT WORKS.

09-18-12 JUST GOT THE PHOTO CELL IN FROM HARRY YARNELL,

HE SENT IT WITH THE FILTER ALSO. THANKS HARRY.

I`LL LET Y`ALL KNOW HOW IT WORKS.

WORKED FINE I NOW HAVE A DIMMING SLIDER.

Edited September 19, 2012 by rusty108
CORECTION/ADD INFO (see edit history)