manual fan switch sets code 28??
Thread Starter
Instructor
Joined: Mar 2001
Posts: 181
Likes: 0
From: Swansea, IL, USA
manual fan switch sets code 28??
just started the car after the switch install, and I'm almost positive I wired it wrong or something, but before I dig into it, has anyone had this problem, and if so how was it fixed? I wired it before the relay, on the wire that runs to the ECM, which grounds the switch. I did the same wiring on both relays, and put them both to one switch... sound OK????? HELP :confused:
Racer
Joined: Jul 2001
Posts: 396
Likes: 1
From: New Hampshire
Re: manual fan switch sets code 28?? (R Cook 92)
This is a pretty good reference to double check your work by.
http://www.madvet.com/pdf/609116.pdf
BTW- I just ran this mod on my 94. It too sets a code.
http://www.madvet.com/pdf/609116.pdf
BTW- I just ran this mod on my 94. It too sets a code.
Racer
Joined: Feb 2002
Posts: 390
Likes: 0
From: St. Louis MO
Re: manual fan switch sets code 28?? (R Cook 92)
Hmmm. I don't know what you guys have got going on here, but I just finished the same mod to my '94 and haven't had any problems. I've had the switch installed for about two weeks and have been using it almost daily (it's been hotter than heck here) in stop and go traffic and it works wonders for keeping the engine cool - and no codes!
I made my wiring change out at the fan relays and picked up a chassis ground at the same point. Ran the wires through the grommet for the hood release cables and installed the switch on the carpeted panel just above the gas pedal.
:)
I made my wiring change out at the fan relays and picked up a chassis ground at the same point. Ran the wires through the grommet for the hood release cables and installed the switch on the carpeted panel just above the gas pedal.
:)
Le Mans Master
Joined: Apr 2000
Posts: 5,713
Likes: 105
From: Manassas VA
Re: manual fan switch sets code 28?? (James94LT1)
Mine sets a code. It does not turn on the check engine light, but when I plug in the Auto X-Ray, sure enough it is set. I am only grounding one of my relays to make it work on mine. I wonder if this effects performance in any way. Also I wondered about using a seperate relay to bring on the fan.
Burning Brakes
Joined: Jan 2000
Posts: 1,159
Likes: 0
From: member since Jan 2000
Re: manual fan switch sets code 28?? (Red 86 4+3)
just to stir the pot a little;
( the '89 has two fans - one EMC controlled and one Temperature Switch controlled -- this deals with the EMC (main) fan )
the problem with installing a switch to override the EMC, by manually pulling the relay to ground, is that you are 'fighting' the EMC - and since it is solid state, there's a potential for 'the unknown'. i'm pretty sure GM engineers have figured out that we fiddle with these things, so there probably is protection for it. but?
i'd say Red 86 4+3 has the 'best' idea;
it is better to install a seperate relay, and parallel the original 'EMC' controlled relay.
another 'safe' method would be to use a 'C-Form' Switch ( a Common terminal with Normally Open AND Normally Closed contact terminals ). this may help avoid any concern here as the switch could disconnect the EMC before grounding the relay.
all that said, obviously some folk have gotten away with the regular 'switch to ground' method, so wth?
( the '89 has two fans - one EMC controlled and one Temperature Switch controlled -- this deals with the EMC (main) fan )
the problem with installing a switch to override the EMC, by manually pulling the relay to ground, is that you are 'fighting' the EMC - and since it is solid state, there's a potential for 'the unknown'. i'm pretty sure GM engineers have figured out that we fiddle with these things, so there probably is protection for it. but?
i'd say Red 86 4+3 has the 'best' idea;
it is better to install a seperate relay, and parallel the original 'EMC' controlled relay.
another 'safe' method would be to use a 'C-Form' Switch ( a Common terminal with Normally Open AND Normally Closed contact terminals ). this may help avoid any concern here as the switch could disconnect the EMC before grounding the relay.
all that said, obviously some folk have gotten away with the regular 'switch to ground' method, so wth?
Thread Starter
Instructor
Joined: Mar 2001
Posts: 181
Likes: 0
From: Swansea, IL, USA
Re: manual fan switch sets code 28?? (R Cook 92)
Well, I'm going to play with it some more, as I looked it over, the switch was obviouly wired wrong by me? I had just rebuilt the motor, and I havent actually taken it to the road yet, so on all my start-ups here in the garage I never bothered to turn it off, cause it the fan kicked on when the ignition turned on, so I figured it was better I leave it on while I let it run in the garage, well, I went today to turn it off, and it doesn't turn off??? so maybe a problem with my work... I can build a whole motor right but can't wire a simple fan switch!!!! Time to have some fun.... hopefully that bad wireing is what is contributing to the code 28...
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