Cooling fan always on? Wtf?
#1
Cooling fan always on? Wtf?
Hey guys!
I've had the strangest things happen to my car since I installed the Megasquirt. For starters, when I turned on the car, the radiator fan would turn on automatically. This didn't really bother me, as I just figured the MS1 probably turned it on all the time...
But now I've just arrived home, turned off the car, and the fan stayed on????
I have no idea what's happening... What could cause the fan to stay on all the time? Could it be a faulty relay? I doubt it could be the Megasquirt, because that is turned off with the ignition I reckon. And I don't think the car has any thermovalve that could cause the fan to keep running. It just doesn't shut off!
What can I do to check where the problem is coming from?
I've had the strangest things happen to my car since I installed the Megasquirt. For starters, when I turned on the car, the radiator fan would turn on automatically. This didn't really bother me, as I just figured the MS1 probably turned it on all the time...
But now I've just arrived home, turned off the car, and the fan stayed on????
I have no idea what's happening... What could cause the fan to stay on all the time? Could it be a faulty relay? I doubt it could be the Megasquirt, because that is turned off with the ignition I reckon. And I don't think the car has any thermovalve that could cause the fan to keep running. It just doesn't shut off!
What can I do to check where the problem is coming from?
#3
Does the Megasquirt even control it? From what I can tell on the service manual, the only things controlling the fan are a pure electrical circuit comprised of a thermoswitch mounted above the thermostat, and a relay. The thermoswitch-to-relay circuit is ignition triggered, and the relay-to-fan circuit is connected to the battery directly. And that's all there is to it, for pre-93 cars, no?
The problem seems to have vanished now though. I replugged everything and it's working fine again. I think the relay might have stuck closed?
The problem seems to have vanished now though. I replugged everything and it's working fine again. I think the relay might have stuck closed?
#8
Boost Czar
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oh... yeah. didnt see that. It will run it when the motor is off and key on....but i think that's just an ms3 option.
if it was running with car off and key out of ignition, it was probably a stuck fan relay.
if it was running with car off and key out of ignition, it was probably a stuck fan relay.
#9
Stuck relay checks out!
The car did it again a few hours ago, only it didn't stop. I took off the battery again, and when the car was cold and I connected the battery, it was still at it. So I thought I'd give a beating to the relay, and what do you know, the fan stopped!
So now I have to just gently tap the relay to get it to unstuck every time I drive the car. Oh well. I need a new relay, and no Mazda dealers around.
The car did it again a few hours ago, only it didn't stop. I took off the battery again, and when the car was cold and I connected the battery, it was still at it. So I thought I'd give a beating to the relay, and what do you know, the fan stopped!
So now I have to just gently tap the relay to get it to unstuck every time I drive the car. Oh well. I need a new relay, and no Mazda dealers around.
#14
Hey guys!
So eventually my relay burned out and got stuck on open, and I was left fan-less :(
I replaced the relay with a new one, and all was fine again!
However, after only two days, the new relay got stuck closed again???? I'm pretty sure it is overheating from the fan being always on.
Brain, does the 9093 MS1 you built control the fan in any way? Because mine just seems to never turn off and I honestly don't know what to do now :(
So eventually my relay burned out and got stuck on open, and I was left fan-less :(
I replaced the relay with a new one, and all was fine again!
However, after only two days, the new relay got stuck closed again???? I'm pretty sure it is overheating from the fan being always on.
Brain, does the 9093 MS1 you built control the fan in any way? Because mine just seems to never turn off and I honestly don't know what to do now :(
#16
I have given a quick look earlier today on my MS configuration and didn't find where I can control the outputs... Where is it? This must seem like a really newbie question to be fair, but since I was given this Megasquirt unit from a car that had undergone extensive modifications, many things had to be fixed by hand and I might have overlooked that one...
EDIT: In fact, I had already checked the settings before, on the Outputs tab of Tunerstudio (I reckon it must be using the JS3 output, right?) and all checks out. Does this mean I have a faulty thermoswitch? And why didn't it happen before with the OEM ECU?
EDIT: In fact, I had already checked the settings before, on the Outputs tab of Tunerstudio (I reckon it must be using the JS3 output, right?) and all checks out. Does this mean I have a faulty thermoswitch? And why didn't it happen before with the OEM ECU?
#17
As I expected, I turned on the ignition, fan started revving, then I unplugged the thermoswitch, see if that killed it...
... It didn't!!!
It was still running with the thermoswitch off. I guess that rules out any problems with the thermoswitch. What am I missing? Which output is programmed for the fan control, Brain?
... It didn't!!!
It was still running with the thermoswitch off. I guess that rules out any problems with the thermoswitch. What am I missing? Which output is programmed for the fan control, Brain?
#20
Boost Czar
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Under basic settings > codebase and outputs, change LED18 from warmup to output 4.
then go to more settings > shift light | fans | output 3 4, under OUTPUT 4, change Use above source or FAN control to Fan control.
on the bottom used like fan on 200 and fan off 190.
burn all changes, power cycle. lmk.
then go to more settings > shift light | fans | output 3 4, under OUTPUT 4, change Use above source or FAN control to Fan control.
on the bottom used like fan on 200 and fan off 190.
burn all changes, power cycle. lmk.