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Unread 08-19-2013, 08:54 PM   #1
dmxsoulja3
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1998 ZJ 
 
Join Date: Oct 2011
Location: Pensacola, Florida
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no cluster or hvac lights at all, lend me a hand

Hey guys, I have lost all of my cluster/hvac lighting, I have bought a new headlight switch that I know is good, tried it on another Jeep. When I turn the lights on the odometer dims like it should but nothing else lights up. Any ideas? Only other thing I did and they worked after was I had to put a new turn signal bulb in the 3454 bulb isn't made anymore so I went with the size everyone else uses not sure if that somehow is making me have no cluster lights but other than a fast blink everything else seems to work.. It sucks at night not being able to see how fast you are going and such, any ideas guys?

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Unread 08-19-2013, 09:19 PM   #2
96zedjay
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Bad BCM?
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Unread 08-19-2013, 09:34 PM   #3
dmxsoulja3
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That was something I read about, that's the box behind the headlight switch right? And it's essential to get one that matches your exact model if you replace it if I remember correctly?
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Unread 08-19-2013, 10:55 PM   #4
Rich93ZJ
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I hope you check your fuses before replacing the BCM. Sounds like you popped a fuse to me.
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Unread 08-20-2013, 05:25 AM   #5
dmxsoulja3
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Not only did I check them, I replaced every single one of them just for good measure down the road. I didn't replace the large ones in the engine compartment but I did check those. Is there a way to test the BCM
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Unread 08-22-2013, 04:48 AM   #6
dmxsoulja3
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Any advice on testing / replacing the BCM? One other thing I thought of and haven't tried because it's a royal pain to pull out because I hid it nicely was a headlight relay harness, the upgraded one that pulls from the battery, the headlights work fine and the odometer and overhead console dim appropriately but I was wondering if that harness removing voltage off the headlight switch is telling the bcm the lights aren't on so no cluster / hvac lighting ? I pulled up the shifter bezel to look at the light under it since it also should come on with headlights and it basically is heating up the element in the bulb and the faintest flicker of light comes from it but it obviously is not what it should be, tried using my multimeter but it's like these sockets are not a measurable 12v current type it just gave me fluctuations of random numbers like pulse width maybe? not sure if anyone has experienced that. Any suggestions would help my fellow Jeep friends!
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Unread 08-22-2013, 06:04 AM   #7
newfieZJ
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I'd say a bad ground . Pretty general since there are quite a few in the system but that's what I would start looking for .
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Unread 09-28-2013, 08:18 PM   #8
ZeeJay1997
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the orange wire is the common feed for the driver.

as you can see, the grounds are from several sources.

now that you know what grounds where, you may be able to further determine where the problem may lie.

let me know which lamps are acting up (based on diagrams below) when and maybe we can run it down or confirm a bad bcm. if there are other lights acting up, let me know so i can throw them in the mix.


When the headlamps or parking lamps are ON, the
The Body Control Module (BCM) receives the park
lamp input on circuit L90 and the illumination lamp
intensity signal on circuit 707. Circuit 707 from the
dimmer switch circuitry in the head lamp switch provides
the illumination lamp intensity signal to the
BCM.
After calculating the requested illumination lamp
intesity, the BCM powers the following illumination
lamps on circuit E2:
Headlamp switch
Floor console
Instrument panel
Ash receiver
Graphic Display or Vehicle Information Center
(VIC)
Cigar lighter
Radio
A/C-Heater control switch
Circuit Z1 provides ground for the floor console
lamps, instrument panel lamps, ash receiver lamp,
graphic display or VIC. Circuit Z4 grounds the automatic
temperature control switch lamp. Circuit Z5
grounds the radio lamp. The cigar lighter lamp and
A/C-Heater control switch lamp (manual A/C-Heater)
are case grounded.
dimmer.jpg

cluster-pod-lighting.jpg

panel-driver-output.jpg

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Unread 09-28-2013, 08:54 PM   #9
dmxsoulja3
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OK awesome, so from what I can tell, every light responsible for illumination is out, so the dash, a/c, console lights are out, but the warning lights, turn signals, airbag type lights are all fine, the gauges themselves work fine too. All of the overhead and footwear lighting works perfectly. Here is the interesting part I can see that the ones that are "out" they are faintly lit meaning if I pull the lighter or shifter console light it's like it is getting just enough voltage to turn the filament orange but not light anything up. I have tried three headlight switches, two new, one resoldered.
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Unread 09-28-2013, 08:58 PM   #10
ZeeJay1997
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check the voltage at terminal socket 15 of the headlight switch harness
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Unread 09-28-2013, 09:09 PM   #11
dmxsoulja3
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OK so pull the switch and un hook it and see what voltage I have or backprobe it while the switch is connected and turn the headlights on?
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Unread 09-28-2013, 09:34 PM   #12
ZeeJay1997
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Quote:
Originally Posted by dmxsoulja3 View Post
OK so pull the switch and un hook it and see what voltage I have or backprobe it while the switch is connected and turn the headlights on?
try it both ways
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Unread 09-29-2013, 06:09 AM   #13
ZeeJay1997
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you can check it all at the headlight switch by back pinning the connector

input 15 , output 8 , and return from bcm 1.
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Unread 09-29-2013, 11:04 AM   #14
dmxsoulja3
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Ok checked it out, input 15 has 12v, output 8 with switch off 0 volts, with switch on 3.38v, return from BCM with switch on .200 volts just kinda fluctuates it seems


EDIT
additionally, I checked all of the connections for continuity with my multimeter and that is good, unplugged the BCM harness to locate the orange wire port 20, that goes to port 10 orange wire on back of cluster connector and there is continuity there, this is the lamp driver wire, however, there is not 12 volts there. I don't know if there should be but seems like it, can someone test for me?
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Unread 09-29-2013, 12:57 PM   #15
ZeeJay1997
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the voltage out of the switch is correct. the bulbs are 3.6v so BCM should provide the max voltage with the slider all the way up.

what are you using for ground for the meter? are you back pinning?
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