D2 Dimmer Switch, Rheostat
#1
03-17-2024, 03:13 PM
D2 Dimmer Switch, Rheostat
Does anyone know if there is a way to bypass the rheostat that controls the Instrument Panel and air control unit light?
Both of mine are dark, I tested the bulbs and they have resistance, so does not appear to be the bulbs, it would be all six going at once anyway.
I get 13.5 volts to the rheostat, dimmer switch on the red wire. When I turn the rheostat the red orange, RO wire, has no voltage at any position. Which it seems to me that there should be some voltage.
Can I for the sake of testing the dimmer switch jump any wires? Or, if I take apart the switch, could I force it to connect at a certain brightness, max brightness is fine.
Also fuse 3 will blow once I turn on the headlights. RAVE seems to show that fuse 3 feeds the fog lamps, the fog lamp relay, headlamps and glove box light. The headlamps work fine, the fog lamp switch is not plugged in. The glove box light does not work, has not for as long as I can remember. What else could be running off of Fuse 3? Or, how would find the cause of my short?
Anything else I should try?
Appreciate the help.
The drivers window works now, the sun roof works now. But the passenger front window still does not work. My thought is to test the voltage of the wire from the BCU to the drivers window and see how that compares to the voltage to the passenger side window. See if there is any difference. I get near zero on the passenger one, I assume I should be getting about 12v on the drivers side.
Both of mine are dark, I tested the bulbs and they have resistance, so does not appear to be the bulbs, it would be all six going at once anyway.
I get 13.5 volts to the rheostat, dimmer switch on the red wire. When I turn the rheostat the red orange, RO wire, has no voltage at any position. Which it seems to me that there should be some voltage.
Can I for the sake of testing the dimmer switch jump any wires? Or, if I take apart the switch, could I force it to connect at a certain brightness, max brightness is fine.
Also fuse 3 will blow once I turn on the headlights. RAVE seems to show that fuse 3 feeds the fog lamps, the fog lamp relay, headlamps and glove box light. The headlamps work fine, the fog lamp switch is not plugged in. The glove box light does not work, has not for as long as I can remember. What else could be running off of Fuse 3? Or, how would find the cause of my short?
Anything else I should try?
Appreciate the help.
The drivers window works now, the sun roof works now. But the passenger front window still does not work. My thought is to test the voltage of the wire from the BCU to the drivers window and see how that compares to the voltage to the passenger side window. See if there is any difference. I get near zero on the passenger one, I assume I should be getting about 12v on the drivers side.
Last edited by redrover75; 03-17-2024 at 04:28 PM.
#2
03-17-2024, 05:47 PM
Which version of the wiring diagram are you using? what you describe doesn't agree with what I'm looking at on mine.
I get 13.5 volts to the rheostat, dimmer switch on the red wire. When I turn the rheostat the red orange, RO wire, has no voltage at any position. Which it seems to me that there should be some voltage.
Can I for the sake of testing the dimmer switch jump any wires? Or, if I take apart the switch, could I force it to connect at a certain brightness, max brightness is fine.
Yes, you can jumper across a rheostat without damaging anything. If you made that jumper permanent, you would have full brightness.
Also fuse 3 will blow once I turn on the headlights. RAVE seems to show that fuse 3 feeds the fog lamps, the fog lamp relay, headlamps and glove box light. The headlamps work fine, the fog lamp switch is not plugged in. The glove box light does not work, has not for as long as I can remember. What else could be running off of Fuse 3? Or, how would find the cause of my short?
My version of the wiring diagram shows fuse 3 in the engine compartment fuse box ONLY serving the fogs.
The drivers window works now, the sun roof works now. But the passenger front window still does not work. My thought is to test the voltage of the wire from the BCU to the drivers window and see how that compares to the voltage to the passenger side window. See if there is any difference. I get near zero on the passenger one, I assume I should be getting about 12v on the drivers side.
Measure across the motor, not to ground. You should see similar results on both sides. If you have a physical limitation, like a bound up regulator, then I don't know what you'll see since the BCU has current limiting on the motor feeds.
Can I for the sake of testing the dimmer switch jump any wires? Or, if I take apart the switch, could I force it to connect at a certain brightness, max brightness is fine.
Yes, you can jumper across a rheostat without damaging anything. If you made that jumper permanent, you would have full brightness.
Also fuse 3 will blow once I turn on the headlights. RAVE seems to show that fuse 3 feeds the fog lamps, the fog lamp relay, headlamps and glove box light. The headlamps work fine, the fog lamp switch is not plugged in. The glove box light does not work, has not for as long as I can remember. What else could be running off of Fuse 3? Or, how would find the cause of my short?
My version of the wiring diagram shows fuse 3 in the engine compartment fuse box ONLY serving the fogs.
The drivers window works now, the sun roof works now. But the passenger front window still does not work. My thought is to test the voltage of the wire from the BCU to the drivers window and see how that compares to the voltage to the passenger side window. See if there is any difference. I get near zero on the passenger one, I assume I should be getting about 12v on the drivers side.
Measure across the motor, not to ground. You should see similar results on both sides. If you have a physical limitation, like a bound up regulator, then I don't know what you'll see since the BCU has current limiting on the motor feeds.
#3
03-17-2024, 06:23 PM
Thanks for this, I do not have a wiring diagram per se. I have been using the RAVE electronics manual. If there is a wiring diagram available that would be super helpful.
To jump the rheostat, would I put a wire connecting the two non-ground wires? Red and Orange Red?
Also, it is Fuse 3 in the passenger compartment, which might be the confusion. What else runs off the 3 fuse that could be causing the short? It seems to only happen when the lights are turned on. The more I read about this on various forums, the Australian one is pretty helpful, the more it sounds like it could be the light switch.
As far as the passenger window. when i connect 12 directly to the harness at the A Pillar, the window works fine. So I don't believe I have a bad motor, I did replace it with a new one, but there could of been a dead on arrival new one. But I do not believe that to be the case. When I test the voltage on the two wires that feed the harness, I get a very low reading about .5v. This is with one probe on each wire. Is there another way to test it? I have replaced the switch, tested a working BCU. Any other ideas?
I am learning as a go on this electrical problem.
Page 4.117
Headlamps - Main Beam Operation
When the lighting switch is moved to the flash or main position, the feed from fusible link 10
in the engine compartment fusebox, passes through the switch contacts. The feed is
connected on a UW wire to the passenger compartment fusebox, where it passes through
fuses 3 and 22.
The IDM senses the headlamp main beam request and through internal circuitry, provides
a feed, on a US wire, to the main beam warning lamp in the instrument pack. The main beam
warning lamp is connected from the instrument pack to earth on a B wire to earth header
C0551.
LH headlamp
The feed from fuse 3 is connected on a US wire from the passenger compartment fusebox
to the LH headlamp and illuminates the LH main beam bulb. The earth path from the LH
headlamp is connected on a B wire to earth eyelet connector C0564-1.
Page 4.120
Front Fog Lamps Operation
When the front fog lamp switch is operated, an earth path is completed from the BCU pin
C0660-7 to the switch on a KB wire. The earth path continues through the switch contacts
and is connected to earth header C0017 LHD/C0018 RHD on a B wire, via header C0760.
The completion of the earth path signals the BCU to provide an earth path from the coil of
the front fog lamp relay in the engine compartment fusebox to the BCU pin C0663-4 on a
UY wire.
The energised coil closes the contacts in the front fog lamp relay. This allows the feed from
fuse 3 to pass through the relay contacts and from the engine compartment fusebox to
header C0293 on a UP wire.
From the header C0293, the feed is connected on a UP wire to the RH front fog lamp, which
connected to earth header C0018 by a B wire.
A second feed from the header C0293 is connected on a UP wire to the LH front fog lamp,
which is connected to earth point C0564 by a B wire.
Page 4.118
OPERATION
Front Fog Lamps Supply
Circuit supply
A feed from the battery positive terminal is connected by an R wire to the engine
compartment fusebox, where it passes through fusible links 1, 7, 8 and 13 and fuses 3 and
13. Fusible links 1 and 7 and fusible link 1 and fuse 3 are connected in series.
A feed from fusible link 13 is connected by an NG wire to the lighting switch.
A feed from fuse 3 is connected to the front fog lamp relay in the engine compartment
fusebox. A feed from fusible link 7 is connected to the auxiliary circuits relay in the engine
compartment fusebox.
To jump the rheostat, would I put a wire connecting the two non-ground wires? Red and Orange Red?
Also, it is Fuse 3 in the passenger compartment, which might be the confusion. What else runs off the 3 fuse that could be causing the short? It seems to only happen when the lights are turned on. The more I read about this on various forums, the Australian one is pretty helpful, the more it sounds like it could be the light switch.
As far as the passenger window. when i connect 12 directly to the harness at the A Pillar, the window works fine. So I don't believe I have a bad motor, I did replace it with a new one, but there could of been a dead on arrival new one. But I do not believe that to be the case. When I test the voltage on the two wires that feed the harness, I get a very low reading about .5v. This is with one probe on each wire. Is there another way to test it? I have replaced the switch, tested a working BCU. Any other ideas?
I am learning as a go on this electrical problem.
Page 4.117
Headlamps - Main Beam Operation
When the lighting switch is moved to the flash or main position, the feed from fusible link 10
in the engine compartment fusebox, passes through the switch contacts. The feed is
connected on a UW wire to the passenger compartment fusebox, where it passes through
fuses 3 and 22.
The IDM senses the headlamp main beam request and through internal circuitry, provides
a feed, on a US wire, to the main beam warning lamp in the instrument pack. The main beam
warning lamp is connected from the instrument pack to earth on a B wire to earth header
C0551.
LH headlamp
The feed from fuse 3 is connected on a US wire from the passenger compartment fusebox
to the LH headlamp and illuminates the LH main beam bulb. The earth path from the LH
headlamp is connected on a B wire to earth eyelet connector C0564-1.
Page 4.120
Front Fog Lamps Operation
When the front fog lamp switch is operated, an earth path is completed from the BCU pin
C0660-7 to the switch on a KB wire. The earth path continues through the switch contacts
and is connected to earth header C0017 LHD/C0018 RHD on a B wire, via header C0760.
The completion of the earth path signals the BCU to provide an earth path from the coil of
the front fog lamp relay in the engine compartment fusebox to the BCU pin C0663-4 on a
UY wire.
The energised coil closes the contacts in the front fog lamp relay. This allows the feed from
fuse 3 to pass through the relay contacts and from the engine compartment fusebox to
header C0293 on a UP wire.
From the header C0293, the feed is connected on a UP wire to the RH front fog lamp, which
connected to earth header C0018 by a B wire.
A second feed from the header C0293 is connected on a UP wire to the LH front fog lamp,
which is connected to earth point C0564 by a B wire.
Page 4.118
OPERATION
Front Fog Lamps Supply
Circuit supply
A feed from the battery positive terminal is connected by an R wire to the engine
compartment fusebox, where it passes through fusible links 1, 7, 8 and 13 and fuses 3 and
13. Fusible links 1 and 7 and fusible link 1 and fuse 3 are connected in series.
A feed from fusible link 13 is connected by an NG wire to the lighting switch.
A feed from fuse 3 is connected to the front fog lamp relay in the engine compartment
fusebox. A feed from fusible link 7 is connected to the auxiliary circuits relay in the engine
compartment fusebox.
#4
03-17-2024, 07:33 PM
Super Moderator
#5
03-18-2024, 09:44 AM
Dimmer
Thanks for the offer.
Strange thing, I pulled the binnacle apart, switches, etc. Messed with the dimmer. Put in new bulbs in the instrument panel, used from another instrument panel I have. I plugged it all back in and tried it, low and behold it worked. even the AC panel surround lights. I put it all back together and hopefully the lights will continue to work, too hard to tell in the day light.
Fuse 3 did not blow, yet.
Passenger window still does not work. At least the other issues are for now fixed.
Strange thing, I pulled the binnacle apart, switches, etc. Messed with the dimmer. Put in new bulbs in the instrument panel, used from another instrument panel I have. I plugged it all back in and tried it, low and behold it worked. even the AC panel surround lights. I put it all back together and hopefully the lights will continue to work, too hard to tell in the day light.
Fuse 3 did not blow, yet.
Passenger window still does not work. At least the other issues are for now fixed.
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