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Marty, Mercedes Technician
Category: Mercedes
Satisfied Customers: 53016
Experience:  Bosch Certified Master Tech. Over 35 years experience.
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300e: I have a 1990 mercdes 300 e with no power to the 30 amp

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I have a 1990 mercdes 300 e with no power to the 30 amp fuse . Where is the 12 v supply for the fuse.

Marty :

Hi, which fuse are you checking? Are you checking the strip fuse outside of the main fuse box?

Customer: Yes the 30 amp external fuse
Marty :

The strip fuse gets power directly from the ignition switch. It originally went to fuse 12 and then the fuse circuit was modified and they relocated the fuse outside of the fuse box. If you have no power to the strip fuse I would lift up the fuse box and see if the pink/green wire is burned where it connects to fuse 12.

Marty :

If the wiring is good and there is no power on the pink/green wire you will need to check for power at the back of the ignition switch. If you have no power with the key on you will need to replace the switch.

Customer: It sounds like it might be easier to run a new 12v supply
Marty :

You could do that as long as you find a fuse with switched power. Keep in mind there is a lot of current running through that fuse. You need to make a good connection wherever you decide to connect it.

Customer: Amy I get back to tomorow I'm not sue how easy it is to get under the fuse block
Marty :

It's not too hard. There should be a screw at the front of the fuse box. Remove the screw and the whole thing just lifts up. Click here for the instructions to replace the ignition switch if needed.

Customer: I Meant may
Marty :

And yes you can reply back tomorrow if you need more help with this.

Customer: Thanks ill start in the am
Marty : You're quite welcome :-)
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