IC pump wiring question
Thread Starter
MBWorld Fanatic!
Joined: Jan 2011
Posts: 2,127
Likes: 4
From: Chicagoland
AMG
IC pump wiring question
I'm looking to throw a simple switch on the ic pump but have a question. I plan on taking a 12v switched from the fuse box with an in line fuse and a switch running to the passenger compatment. But, if I take the switched hot and splice it onto the positive wire on the IC harness, will it work like I think (when switch is on pump runs all the time with key in acc, and when switch is off, ECU controls pump activation)? Also, will the ecu think the source of the 12v in the fuse box is drawing to much power and shut it off or throw a MIL?
Super Member
Joined: Mar 2007
Posts: 575
Likes: 2
From: Lake Norman
CTS-V 2013 Wagon
Doesn't sound like a good idea to me. If you want to power the pump with a separate power source, then I would eliminate the factory power source.
If you power the pump with a 12 volt source at the factory source, you will be throwing 12 volts to the circuit that the ecu controls.
You could accomplish what you are trying to do with an inline diode on the stock power source, so it is possible.
Several of the guys have their pumps setup to run constantly when the key is on, which is an easy way to do it.
If you power the pump with a 12 volt source at the factory source, you will be throwing 12 volts to the circuit that the ecu controls.
You could accomplish what you are trying to do with an inline diode on the stock power source, so it is possible.
Several of the guys have their pumps setup to run constantly when the key is on, which is an easy way to do it.
Thread Starter
MBWorld Fanatic!
Joined: Jan 2011
Posts: 2,127
Likes: 4
From: Chicagoland
AMG
I'm trying to make it so I do not have to run it all the time though. maybe 2 switches, one before the other so if the ecu tells the pump to turn on while it's already on it won't shove 24 volts in my pump.
Super Member
Joined: Mar 2007
Posts: 575
Likes: 2
From: Lake Norman
CTS-V 2013 Wagon
It doesn't work that way, you won't "shoot 24 volts". The problem I see is you will power up the stock circuit with 12 volts when you turn your switch on.
Think of electricity like flowing water. A diode is a one way check valve for electricity. If you put a diode in the stock circuit, electricity would only flow from the source to the pump when the ecu opened the circuit. When you flip your switch on, electicity would flow to the pump and the diode but the diode would not allow the electricity to go to the stock circuit.
Think of electricity like flowing water. A diode is a one way check valve for electricity. If you put a diode in the stock circuit, electricity would only flow from the source to the pump when the ecu opened the circuit. When you flip your switch on, electicity would flow to the pump and the diode but the diode would not allow the electricity to go to the stock circuit.
Super Member
Joined: Mar 2007
Posts: 575
Likes: 2
From: Lake Norman
CTS-V 2013 Wagon
Bottom line is it would be much easier to power the pump to run all the time that the engine is running. I'm a bit surprised more folks don't do this. I guess I should look at doing this myself.
Trending Topics
MB World Stories
The Best of Mercedes & AMG
7 Craziest Things AMG Gas Ever Built
Verdad Gallardo
New Electric Mercedes-AMG GT 4-Door Coupe Unveiled: 10 Things You Need to Know
Verdad Gallardo
6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)
Verdad Gallardo
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
Super Member
Joined: Mar 2009
Posts: 937
Likes: 15
From: Alpharetta Georgia
2006 E55, 2006 saab 93 aero, 2010 glk 4m
Wouldn't getting a relay that supports 2 triggers get you the effect you are looking for? I forget the name of that type of relay but basically the idea is
Stock positive wire routes to input 1.
Switched 12v source goes to trigger 2. Single output from relay goes to + ve of pump.
Stock positive wire routes to input 1.
Switched 12v source goes to trigger 2. Single output from relay goes to + ve of pump.
MBWorld Fanatic!
Joined: Apr 2009
Posts: 1,258
Likes: 5
E55
+1 ^^^ A standard automotive relay would work fine.
To the OP, are you assuming that the ECU is controlling the pump through the hotside 12+? I have not tested it, but it could be recieving + voltage all the time and controlled via the ground side.
To the OP, are you assuming that the ECU is controlling the pump through the hotside 12+? I have not tested it, but it could be recieving + voltage all the time and controlled via the ground side.
Thread Starter
MBWorld Fanatic!
Joined: Jan 2011
Posts: 2,127
Likes: 4
From: Chicagoland
AMG
I stopped ove at radioshack and bought an in line fuseholder rated to 30 amps, two 1 amp 300 volt diodes, a switch, some wiring and heatshrink tubing, and a multimeter. Doing this in a few minutes, and then if it works off to spank a GTO at 3 O'clock.
Junior Member
Joined: Aug 2011
Posts: 72
Likes: 0
From: SO CAL
2006 E55 AMG
did you verify this ? wondering if just cutting the stock trigger wire for the i/c pump (is it the ground or positive ?) and just wiring to a constant ign on . imo thats the best way .
MBWorld Fanatic!
Joined: Mar 2011
Posts: 1,315
Likes: 4
E55, SL63, ML550
I just wired mine to run with ign on(circuit 15). I removed the red/stripe wire from the pump connector and taped off. Installed new pin/wire into connector, and wired into fuse box at drivers side of hood. This seemed to be easiest for me.
Last edited by Shifter; Oct 31, 2011 at 11:33 PM. Reason: typo
