Wiring problem
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From: Tomball/Nacogdoches TX
Wiring problem Few days ago I wired my own fan switch. I used a specific 3 prong LED switch that I had in my custom switch plate. Since the wire for the high fans has to be grounded in order to work, I used a relay to allow the switch to activate a ground wire. Here's the relay I used:
BUT it throws a PO481 code everytime I turn it on:
The PCM has determined that a malfunction exists in the control circuit for cooling fan 2.
Definition:
Cooling fan primary circuit condition
Explanation:
The engine cooling fan relay circuit is monitored for opens and shorts
Probable Causes:
1. Cooling fan relay defective
2. Check connector and wiring.
Is there any way to make it stop throwing this code without having it deleted?
BUT it throws a PO481 code everytime I turn it on:
The PCM has determined that a malfunction exists in the control circuit for cooling fan 2.
Definition:
Cooling fan primary circuit condition
Explanation:
The engine cooling fan relay circuit is monitored for opens and shorts
Probable Causes:
1. Cooling fan relay defective
2. Check connector and wiring.
Is there any way to make it stop throwing this code without having it deleted?
Joined: Nov 2003
Posts: 11,325
Likes: 342
From: Jacksonville, FL (originally from Toronto Canada)
You need to add diodes in the original wires to the PCM after the point where you tapped in with your manual switch wire (i.e. between your splice and the PCM). The problem is that the PCM sees a "short" to ground in the fan relay control wire. Adding a diode allows the PCM to ground the relay normally but prevents it from seeing the ground you provide when you manually operate the fans.
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From: Tomball/Nacogdoches TX
I knew you would come through and help. Thanks man.
I have never used a diode before. I looked them up on radioshack and do not know which one to get. Any suggestions?
http://www.radioshack.com/search/ind...gkw=diode&sr=1
I have never used a diode before. I looked them up on radioshack and do not know which one to get. Any suggestions?
http://www.radioshack.com/search/ind...gkw=diode&sr=1
Joined: Nov 2003
Posts: 11,325
Likes: 342
From: Jacksonville, FL (originally from Toronto Canada)
You should get 3-amp diodes like these. They go inline in the wires from the fan relays to the PCM after (closer to the PCM) where you spliced in your switch.
Current flows through a diode from the anode to the cathode but not the other way - it's like a one-way valve for electricity. You want current to flow from the fan relays to the PCM but not the other way so install the diodes with the stripe (cathode) pointing toward the PCM. Also, be sure that they are thoroughly insulated after installation - you don't want them to short out against some metal.
Current flows through a diode from the anode to the cathode but not the other way - it's like a one-way valve for electricity. You want current to flow from the fan relays to the PCM but not the other way so install the diodes with the stripe (cathode) pointing toward the PCM. Also, be sure that they are thoroughly insulated after installation - you don't want them to short out against some metal.
