| PontiacBonnevilleClub.com http://www.pontiacbonnevilleclub.com/forum/ |
|
| Blower Control Module Bypass Fix http://www.pontiacbonnevilleclub.com/forum/1992/topic8994.html |
Page 1 of 1 |
| Author: | RegencyRoyale [ Sat Jan 31, 2009 12:01 am ] |
| Post subject: | Blower Control Module Bypass Fix |
Hey, A few months ago when the blower control module went out the guy at the garage just put in a toggle switch to bypass it. It was a temporary solution. Simple enough. Trouble is now I got another BCM to pop in there to right the original problem and the guy who originally installed the switch is long gone and I don't really know what he did or how he wired up the blower to the switch. I only know that the line he ran for it goes through the glove box and there is a fuse holder in there. I want to disconnect it. Is there just one way the switch might have been set up or many possibilities? Thanks |
|
| Author: | gmman [ Sat Jan 31, 2009 1:08 am ] |
| Post subject: | Re: Blower Control Module Bypass Fix |
in the configuration that you have (with the bypass switch) does the blower always operate in the fast or high mode? if so he probably just picked up 12 volts somewhere around the dash and wired it thru the fuse and switch directly to the blower motor. if he blower operates medium speed, he may have wired in a resistor as well. inspect the harness at the point where it plugs into the blower motor control module and see if this might be his tie point. you should find a strange wire attached to the blower motor control module connector. if so cut or otherwise remove it and cap it off with electrical tape. then remove his fuse, install new blower control module and system should operate normally. you do not have to necessarily remove all his bypass wiring except to restore car to original. another possibility, he might have gone directly to the blower motor to tie in his 12 volts. if so, clip stange wire and follow above. third possibility, he might have actually pulled 12 volts from the relay center (located in the engine bay against the firewall (this is where 12 volts is normally accessed to blower motor thru blower control module). if so he would have had to pull a wire thru firewall to glove box vacinity and then thru fuse and switch and back thru firewall to some connection that feeds blower motor. hope this gives you some ideas to work with. if not successful, post back with findings. |
|
| Author: | RegencyRoyale [ Sat Jan 31, 2009 1:30 am ] |
| Post subject: | Re: Blower Control Module Bypass Fix |
The switch is either full on or nothing. No medium settings. It only works with the car running too, not like the seats or mirrors. I'll have a look in daylight for any additional wires and post back what I find. Thanks |
|
| Author: | gmman [ Sat Jan 31, 2009 1:54 pm ] |
| Post subject: | Re: Blower Control Module Bypass Fix |
since you see that blower is full on or nothing, there is probably no resistor in his circuit. also, since you have nothing unless car is running, it probably means he tapped in to 12 volts that is only available with key in run position. that info narrows his ciruit configuration somewhat. you would probably be safe just to pull his added fuse if you can't find where he cut into the blower motor circuit (provided he did not interrupt the blower circuit where he tied in). if he did cut into the blower circuit, you will have to find where and re-establish continuity for your new BMC module to work properly. good luck! |
|
| Author: | RegencyRoyale [ Sat Jan 31, 2009 3:50 pm ] |
| Post subject: | Re: Blower Control Module Bypass Fix |
I went out and took a look and there are no additional wires running to the blower motor, just the regular plug-in. I also don't see anything going to the BCM so I'm quite unsure where the temporary line originates. Is there any danger in installing the new BCM as long as the toggle switch is in the OFF position? I realize that if the blower circuit has been cut it might not work, but can it hurt to try it? Thanks. |
|
| Author: | gmman [ Sat Jan 31, 2009 6:34 pm ] |
| Post subject: | Re: Blower Control Module Bypass Fix |
i cannot think of a problem with just leaving switch off. however, to my knowledge there is no wiring access to the blower motor except in the engine bay. so that means he must have gotten into the harness as it exits dash thru the firewall and then to the blower motor control module. there is a red wire that runs from a 30 amp fuse in the relay panel mounted along the firewall into a harness that emerges from the passenger side firewall and to various points in the engine bay. the red wire feeds 12 volts (hot at all times) to the blower motor control module. the blower motor control module then feeds voltage to the blower motor thru a purple wire that runs in that same harness and out to the blower motor. he could have parellel wired the switchable 12 volts (from where ever he tapped into it) to the purple wire which feeds the blower motor. if he parallel wired to the purple wire you can shut off toggle switch and your new BMC module should operate normally. if he cut the purple wire, you will have to reconnect. the wires in the harness can be accessed by peeling off the black wire lace. i am not dead positive of the color of the voltage feed to the blower motor. usually of the two wires feeding the blower motor one will be black (ground) and the other will be purple or maybe red (12 volts or 12 volts as modified by the blower motor control module). his circuit would have to tie into the purple wire at some point. will keep trying to figure it out base on your findings. |
|
| Author: | gmman [ Sat Jan 31, 2009 7:02 pm ] |
| Post subject: | Re: Blower Control Module Bypass Fix |
just had another thought as to why your new BCM may not function. there is a feedback wire that is part of the climate control system. it is tapped off the BCM output and fed to climate control computer. he could have used that wire to feed 12v thru the firewall from the switch he installed. hope not but post your observations as you proceed. |
|
| Author: | RegencyRoyale [ Sat Jan 31, 2009 8:28 pm ] |
| Post subject: | Re: Blower Control Module Bypass Fix |
Wow, thanks for all that info. It will be very helpful. Right now the car is not being used, no need to expose it to winter roads, so I'll be taking it to a garage around the end of February to get it checked out before spring. If I don't sort it myself before then I might just wait and let them deal with it. It's probably too cold for me to do much with it right now anyway. Thanks again for all the information. Cheers! |
|
| Page 1 of 1 | All times are UTC - 5 hours [ DST ] |
| Powered by phpBB® Forum Software © phpBB Group http://www.phpbb.com/ |
|