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Discovered this quick and easy cooling mod after doing a bit of research into the pump the car is equipped with. Turns out that you only need to disconnect the PWM signal to the pump in order to switch it to a max power / always on mode. Common mod on any air to water intercooler equipped cars, so I was surprised that nobody has discovered it. Goes to show the sad state of M276 modding I guess, wish we got more "easy" mods for these cars like my C32 and CL55, which had tons of easy mods to make the cars better. Anyways, I did notice that the temps recover much quicker with the mod and IAT's sit a bit lower than before, also might help a bit with temp recovery after a race or sitting in staging lanes. Not going to make a massive difference but it is noticeable for me and your car will be happier with it.
Posted the video below but really all you need to do is "disconnect" the black and yellow wire going to your intercooler pump, which is behind the passenger side bumper grill accessible from underneath after removing the skid trays. You can make a simple harness using connectors if you want to go back to factory whenever you want, and you could make it even better and put a switch between the black wires to go back to OEM whenever you flip the switch but I decided not to as I want the cooling at all times and the pumps are cheap so I don't care about longevity. This sets the pump to an on/off mode, and the car already supplies switched 12v power to the pump with the key in accessory so the pump will turn on and run at full power. Have not thrown any codes for a week and 600 miles of driving (and a few races in Mexico). Video has more info.
Curious how long the pump lasts like that. Would be nice to have an in car switch for this. Id guess they went with pulse width to extend pump life and to help with noise at idle/ acc on.
Would also be curious what the signal looks like during normal driving. Id assume its modulated based on IAT and load.
Discovered this quick and easy cooling mod after doing a bit of research into the pump the car is equipped with. Turns out that you only need to disconnect the PWM signal to the pump in order to switch it to a max power / always on mode. Common mod on any air to water intercooler equipped cars, so I was surprised that nobody has discovered it. Goes to show the sad state of M276 modding I guess, wish we got more "easy" mods for these cars like my C32 and CL55, which had tons of easy mods to make the cars better. Anyways, I did notice that the temps recover much quicker with the mod and IAT's sit a bit lower than before, also might help a bit with temp recovery after a race or sitting in staging lanes. Not going to make a massive difference but it is noticeable for me and your car will be happier with it.
Posted the video below but really all you need to do is "disconnect" the black and yellow wire going to your intercooler pump, which is behind the passenger side bumper grill accessible from underneath after removing the skid trays. You can make a simple harness using connectors if you want to go back to factory whenever you want, and you could make it even better and put a switch between the black wires to go back to OEM whenever you flip the switch but I decided not to as I want the cooling at all times and the pumps are cheap so I don't care about longevity. This sets the pump to an on/off mode, and the car already supplies switched 12v power to the pump with the key in accessory so the pump will turn on and run at full power. Have not thrown any codes for a week and 600 miles of driving (and a few races in Mexico). Video has more info.
After seeing this today I wanted to check it out. Found the pump by removing 3 plastic rivets from the wheel well. I could not get the plug off and didnt want to cut the wire without an easy way to reconnect it should I need to. I followed the wires and found they come up and into the battery compartment. Remove the cover and its the bundle of wire closest to the motor. Strip back the tape, cut and insulate the black/yellow wire, retape the bundle. There is only one Black/Yellow wire in there. I cut that one and then turned the ignition on and the pump went full speed and works as shown above.
After seeing this today I wanted to check it out. Found the pump by removing 3 plastic rivets from the wheel well. I could not get the plug off and didnt want to cut the wire without an easy way to reconnect it should I need to. I followed the wires and found they come up and into the battery compartment. Remove the cover and its the bundle of wire closest to the motor. Strip back the tape, cut and insulate the black/yellow wire, retape the bundle. There is only one Black/Yellow wire in there. I cut that one and then turned the ignition on and the pump went full speed and works as shown above.
After seeing this today I wanted to check it out. Found the pump by removing 3 plastic rivets from the wheel well. I could not get the plug off and didnt want to cut the wire without an easy way to reconnect it should I need to. I followed the wires and found they come up and into the battery compartment. Remove the cover and its the bundle of wire closest to the motor. Strip back the tape, cut and insulate the black/yellow wire, retape the bundle. There is only one Black/Yellow wire in there. I cut that one and then turned the ignition on and the pump went full speed and works as shown above.
Thanks OP for the video!
Do you know if on C43 2017 is the same as you mention in the pics?
After seeing this today I wanted to check it out. Found the pump by removing 3 plastic rivets from the wheel well. I could not get the plug off and didnt want to cut the wire without an easy way to reconnect it should I need to. I followed the wires and found they come up and into the battery compartment. Remove the cover and its the bundle of wire closest to the motor. Strip back the tape, cut and insulate the black/yellow wire, retape the bundle. There is only one Black/Yellow wire in there. I cut that one and then turned the ignition on and the pump went full speed and works as shown above.
Thanks OP for the video!
Awesome! Glad you found an easier way. Yeah the connector was a pain in the *** to unclip, it’s easier from below; but yours is a much better way to do it. I didn’t want to cut the factory harness so I did it my way but I probably should have just done this. Update us after some more testing, I want to know how it functions for other people.
Curious how long the pump lasts like that. Would be nice to have an in car switch for this. Id guess they went with pulse width to extend pump life and to help with noise at idle/ acc on.
Would also be curious what the signal looks like during normal driving. Id assume its modulated based on IAT and load.
I’m pretty sure the reason they would modulate the pump speeds is for emissions and not to help with cooling. I let the car sit for a while and never observed the pump go over very low flow, maybe during a full throttle pull it ramps up but that’s too little too late. I’m not too worried about longevity, the pumps are relatively cheap and are a modern design, they should last longer running at a more constant 13.8 voltage instead of fluctuating through speeds as they probably did before. The single speed pump in my C32 lasted over 120k miles and 17 years and that was a design from 20 years ago vs a modern pump from a reputable company like bosch.
After seeing this today I wanted to check it out. Found the pump by removing 3 plastic rivets from the wheel well. I could not get the plug off and didnt want to cut the wire without an easy way to reconnect it should I need to. I followed the wires and found they come up and into the battery compartment. Remove the cover and its the bundle of wire closest to the motor. Strip back the tape, cut and insulate the black/yellow wire, retape the bundle. There is only one Black/Yellow wire in there. I cut that one and then turned the ignition on and the pump went full speed and works as shown above.
Thanks OP for the video!
Forgot to ask, did you disconnect the battery first?
Is it the same color wire-on the FL that needs to be insulated?
best way to know would be turn the wheels all the way left, 3 clips on the fender liner to pull it out and see what color the middle wire is on the plug on the pump.
best way to know would be turn the wheels all the way left, 3 clips on the fender liner to pull it out and see what color the middle wire is on the plug on the pump.
I’ll take a look today.
unless someone beats me to it. Lol
Last edited by MaverickC43; Jun 6, 2023 at 08:16 AM.
Reason: Forgot
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
5 minute cooling mod (Always on IC pump)
