PCM Cooling Fan Wire Hot When Off
#1
PCM Cooling Fan Wire Hot When Off
I was attempting to install a lighted push button switch for my elec fan and I was surprised to see it light up when the ignition was turned off! Why is my pcm fan gnd putting out 12V when off? Ive attached a diagram of how I have it wired. Its working fine. I simply have the fan hi switched to gnd.
#3
#4
The PCM is not powering them with +12V.
This type of outputs are grounded by the PCM to activate them, when deactivated they go to a "floating state" and the voltage you see at the pins is a residual or leaked voltage that passes thru the relay coil. If you want the bulb to remain off then you should use a IGN wire to power the relay 86 terminal from your drawing instead of having it permanent from battery.
This type of outputs are grounded by the PCM to activate them, when deactivated they go to a "floating state" and the voltage you see at the pins is a residual or leaked voltage that passes thru the relay coil. If you want the bulb to remain off then you should use a IGN wire to power the relay 86 terminal from your drawing instead of having it permanent from battery.
#5
The PCM is not powering them with +12V.
This type of outputs are grounded by the PCM to activate them, when deactivated they go to a "floating state" and the voltage you see at the pins is a residual or leaked voltage that passes thru the relay coil. If you want the bulb to remain off then you should use a IGN wire to power the relay 86 terminal from your drawing instead of having it permanent from battery.
This type of outputs are grounded by the PCM to activate them, when deactivated they go to a "floating state" and the voltage you see at the pins is a residual or leaked voltage that passes thru the relay coil. If you want the bulb to remain off then you should use a IGN wire to power the relay 86 terminal from your drawing instead of having it permanent from battery.
#7
TECH Enthusiast
Relays are just switches, depending on how you wire them, they are a open / close circuit. Open contacts do not bleed voltage, unless their shorted (welded together) or broken. The coils need power in and a source on ground. The only way a relay can maintain power when voltage is remove, it will be known as a timer relay which has a capacitor (that hold current) in it to maintain voltage at a timed / determined period.
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#8
You can try a solid state relay, but the solution is there, use a IGN feed instead of a direct connection from battery which you should not be doing anyways.
#9
Relays are just switches, depending on how you wire them, they are a open / close circuit. Open contacts do not bleed voltage, unless their shorted (welded together) or broken. The coils need power in and a source on ground. The only way a relay can maintain power when voltage is remove, it will be known as a timer relay which has a capacitor (that hold current) in it to maintain voltage at a timed / determined period.
I guess you are right, I should just switch them to IGN.
#10
TECH Enthusiast
[QUOTE=JensenB;20086962]Well, as soon as I unplug the relay, with IGN OFF (with pcm) the switch light goes out. Ive tried another relay and it did the same. I will have to bench test these to confirm..
I need the make & model # of the switch. to see how it should be wired.
I need the make & model # of the switch. to see how it should be wired.