sterlingc1975

My stock pump wasn't turning on so ordered Johnson cm30 pump and still nothing.. Checked fuse it's fine... Any ideas? I would like any input...

Thanks..

Autotechnica

my pump was completely shot and didn't turn on either. Just last night I replaced mine with the CM30, everything works great now! I tested my CM30 pump prior to installation. It's a long shot, but you could test to see if the pump even works?

good luck!

loudandheard

You could have a burnt out fuse, I can't remember where the fuse is located, but check both areas for a burnt fuse. Hopefully another member can chime in which fuse it is and where it's located.

Autotechnica

???

He already said he checked his fuse.

FYI fuse is #5, 7.5amps located in trunk

loudandheard

Don't know how I missed that one.

Maybe he checked the wrong fuse? Maybe you have a bad pump, but another way find out is to see if you have voltage coming from the wires, they are simply a positive and a ground.

sterlingc1975

How did you perform test to check pump?
Thanks everyone who responded! I love this forum everyone so helpful...

Autotechnica

Prior to installation I simply hooked up the CM30's wire leads to a 12V battery. I used a car battery but any 12V power source should work. There doesn't need to be any water, just make sure the motor switches on. It should be really strong, there should be a noticeable jolt. Don't run the motor dry too long, it's not good for it. Aside from that, I can only assume that there's something wrong with the original connector/wires. If you want to test for voltage comming from the original pump wires, the car will have to be running for you to do this. Test with a multimeter. I don't think the pump switches on until you reach past 2500RPM after switching the car on. Can anyone confirm this? If all else fails, since you already have the hard part done (installing the new pump), you might consider bringing it in to a mechanic or mercedes.

EDIT, something I forgot to mention. The CM30 comes in both 12V and 24V configurations. Make sure that you purchased the 12V model! It will be indicated on the box, the sticker on the pump as well as the user manual.

Bry

loungn14

just wire it for 12v ignition switched power. Your better off anyway with that, cools better.

sterlingc1975

[QUOTE=Autotechnica;4210571]Prior to installation I simply hooked up the CM30's wire leads to a 12V battery. I used a car battery but any 12V power source should work. There doesn't need to be any water, just make sure the motor switches on. It should be really strong, there should be a noticeable jolt. Don't run the motor dry too long, it's not good for it. Aside from that, I can only assume that there's something wrong with the original connector/wires. If you want to test for voltage comming from the original pump wires, the car will have to be running for you to do this. Test with a multimeter. I don't think the pump switches on until you reach past 2500RPM after switching the car on. Can anyone confirm this? If all else fails, since you already have the hard part done (installing the new pump), you might consider bringing it in to a mechanic or mercedes.

EDIT, something I forgot to mention. The CM30 comes in both 12V and 24V configurations. Make sure that you purchased the 12V model! It will be indicated on the box, the sticker on the pump as well as the user manual.





Bry


Thanks again!,

gt4awd

Check to ensure you connected it correctly. The original wiring is red and brown. Red is positive, and brown is negative. Some pumps will run reversed if you reverse wiring, and some designs will not function at all... I installed a switch in the engine bay to manually run the pump for cool down with engine off. Took around 15 minutes to install, and cost $5 dollars for the switch at autozone. Simple mechanical single pole on/off switch. Placed it on the small plastic piece by battery where the hood shock rests when closed. Tapped into the positive at distribution point by battery under the red cap as it's always active. You can just run positive down to pump positive. No need to mess with the ground...

02C32guy

The fuse in the rear sam is the main one, but if you look at the fuse diagrams there are other ones that seem to be associated. I've never been able to tell if they actually are or not, but couldn't help to check those. Do a search on this forum for the diagrams. I've uploaded them several times. Also, I had this problem once, and it turned out that when they replaced my rear sam they didn't plug something into the sam the correct way.