Rear Fan Switch, Inop... any ideas? (2 Viewers)
- Thread starter 2001LC
- Start date
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aging fleet
SILVER Star
Any chance the controls in the third row are set to off? It’s been awhile since I’ve looked at mine, but I think there is an off setting. May be worth a look before you start tearing in.
I don't know about 07, but in my 2000, if I hit the rear button on dash, it will turn on the rear AC or heater (whats selected in the overhead switch) and fan at high.
Do you have to have the front AC working do get the rear working?
Do you have to have the front AC working do get the rear working?
X2, does it have the overhead controls in the headliner? the dash switch on the older rigs is more of a master to turn the overhead controls on.
If the button stays lighted when you press it next up would be power to the rear upper control box.
I never looked for a rear fan fuse before, I bet there is one. Probably a controller and resistor pack also.
You probably checked all the usual suspects I bet from the book.
I'd try to check everything before getting at the rear evap housing.
HVAC code check from the front center console might get you somewhere.
I always have the rear upper HVAC set to hi ac. Then when you hit the front "rear" button the fan roars up to speed.
The "rear" button just sends power to the rear upper control panel, I think. Then the rear ac amp takes over with input from the rear upper controls.
(Guessing without searching
May contain errors)
I never looked for a rear fan fuse before, I bet there is one. Probably a controller and resistor pack also.
You probably checked all the usual suspects I bet from the book.
I'd try to check everything before getting at the rear evap housing.
HVAC code check from the front center console might get you somewhere.
I always have the rear upper HVAC set to hi ac. Then when you hit the front "rear" button the fan roars up to speed.
The "rear" button just sends power to the rear upper control panel, I think. Then the rear ac amp takes over with input from the rear upper controls.
(Guessing without searching
May contain errors)
- Thread starter
- #6
You guy's got me to thinking. I only tried while rear in auto.
So I tried with rear fan manually pressed on HI. That is, to press the HI fan button on ceiling control panel in rear. I was able to turn fan off and on once each. But most times I press center dash rear fan button, it does nothing.
So this may be a case of lack of use. Like we see when the CDL button, when it is not used! Could be if I keep working it will improve. @abuck99 had suggested that could be the case "sticky switch"
The dash "rear" fan button must either go though the amplifier (behind NAV unit) or a relay somewhere. Anyone one know?
So I tried with rear fan manually pressed on HI. That is, to press the HI fan button on ceiling control panel in rear. I was able to turn fan off and on once each. But most times I press center dash rear fan button, it does nothing.
So this may be a case of lack of use. Like we see when the CDL button, when it is not used! Could be if I keep working it will improve. @abuck99 had suggested that could be the case "sticky switch"
The dash "rear" fan button must either go though the amplifier (behind NAV unit) or a relay somewhere. Anyone one know?
Rear ac amp is with the rear housing behind all the plastic.
Same mag clutch in the main fuse box though.
...Button under the green light.... If it's working normally and not sticky the green light should come on consistantly.
And rear fan will default to whatever the upper rear controls are set on.
Very back of the wiring books for those years, last color diagrams.
Same mag clutch in the main fuse box though.
...Button under the green light.... If it's working normally and not sticky the green light should come on consistantly.
And rear fan will default to whatever the upper rear controls are set on.
Very back of the wiring books for those years, last color diagrams.
- Thread starter
- #8
"Rear ac amp is with the rear housing behind all the plastic." Are you speaking of rear PS cargo area at AC unit behind plastic interior panels?
"Same mag clutch in the main fuse box though." Your speaking of the AC clutch, this one right?
This was from a 05 IIRC
".Button under the green light.... If it's working normally and not sticky the green light should come on consistantly." Light on button works fine. It tells me if a rear fan on or off, AC or Heater.
Yes, and yes,
And the "rear" button only gives you power to the ceiling control box. Whatever happens next is dependent on the settings in the ceiling rear control panel.
The front center console rear button is a true master switch. Far as I know.
And the "rear" button only gives you power to the ceiling control box. Whatever happens next is dependent on the settings in the ceiling rear control panel.
The front center console rear button is a true master switch. Far as I know.
- Thread starter
- #10
I guess the question is: What relay, amplifier, cpu, etc does the dash switch go though to activate the rear control?
I understand the rear ceiling control panel settings (temp. fan) is not changed by dash switch, dash switch will activate those pre sets only. That the dash switch is just a remote fan on or off.
I understand the rear ceiling control panel settings (temp. fan) is not changed by dash switch, dash switch will activate those pre sets only. That the dash switch is just a remote fan on or off.
I'd consult the wiring book, it's all in there.
There is a rear ac amp. Either amp can trigger the single mag clutch relay.
The front ac amp and heater integration panel must at least be partially working for the rear ac amp to get inputs.
Think of the upper rear controls as duplicates of the front center control panel. They both do the same thing. Only partially dependent on each other.
Share the same relay. Have separate blowers, resistors, blower controllers, evaporators. Thermistors, ambient temp probes , etc.
The wiring book will get you info.
Self check HVAC codes and fuse check for rear blower if one exelists before any taking out plastic stuff.
Maybe there's techstream checking for the rear. I kind of doubt it.
There is a rear ac amp. Either amp can trigger the single mag clutch relay.
The front ac amp and heater integration panel must at least be partially working for the rear ac amp to get inputs.
Think of the upper rear controls as duplicates of the front center control panel. They both do the same thing. Only partially dependent on each other.
Share the same relay. Have separate blowers, resistors, blower controllers, evaporators. Thermistors, ambient temp probes , etc.
The wiring book will get you info.
Self check HVAC codes and fuse check for rear blower if one exelists before any taking out plastic stuff.
Maybe there's techstream checking for the rear. I kind of doubt it.
- Thread starter
- #12
Yeah I've been trying to read the wire diagram (DW), not my strong suit.
I'm also having band with issue connecting to my source of TIS (WD). Likely due to so much internet traffic with so many at home due to "War V". If you've time and you see something please post up.
I'm also having band with issue connecting to my source of TIS (WD). Likely due to so much internet traffic with so many at home due to "War V". If you've time and you see something please post up.
- Thread starter
- #15
Working now after cleaning..
I pulled the NAV unit. Then disassembled the lower end of it, to point lower circuit board came out. I then removed the rubber cap, which has fan switch contacts. Sprayed with electric contact cleans, then blew out with HP air while wet. Switch works ever time now.
Seems cleaning worked. As switch now is working on every push.
Sorry I did not get any pictures. Her's 2 pic I found in mud of the cap (blue) and contacts.
I removed the cap and sprayed the contacts while in place on the board.
I pulled the NAV unit. Then disassembled the lower end of it, to point lower circuit board came out. I then removed the rubber cap, which has fan switch contacts. Sprayed with electric contact cleans, then blew out with HP air while wet. Switch works ever time now.
Seems cleaning worked. As switch now is working on every push.
Sorry I did not get any pictures. Her's 2 pic I found in mud of the cap (blue) and contacts.
I removed the cap and sprayed the contacts while in place on the board.
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