Where do you buy a fuse box for 1985 300CD - PeachParts Mercedes-Benz Forum

frnorke · #1 03-14-2014, 11:52 AM

My fuse box seems to have started melting a little. It's causing the 25 A blower fuse to keep burning up.

Does anyone know where to buy the fuse box (or board or whatever it's called) and can I replace this from the engine side of the firewall?

Thanks.
Kurt

charmalu · #2 03-14-2014, 12:08 PM

I doubt they are available from the Dealer, so your best bet is a Junk Yard IE PNP. or look in the For sale section and put up a want to buy WTB. there is always someone parting out a w123.

Look on CL for cars being parted. E_Bay is usually over priced on everything.

Where do you live? maybe some one close to you may even have what you need.

Charlie

frnorke · #3 03-14-2014, 12:13 PM

Thanks for the advice. I live in Virginia if anyone around here has one for sale.

frnorke · #4 03-14-2014, 02:11 PM

Hi,
Does anyone know the part number for the fuse box on a 1985 300CD?

Thanks.
Kurt

jay_bob · #5 03-14-2014, 03:15 PM

Does your fuse card in the box call for a 25 A fuse? I thought the blower fuse on the 123 was a 16 A.

Do you have a subscription to EPC? epc.startekinfo.com

It asks for a credit card but only to prove you are in the US. It creates a temporary authorization for $1 but does not convert to a charge.

Diesel911 · #6 03-14-2014, 03:50 PM

If the Blower Fuse is burning you need to fix the Blower Motir so it won't do that.

Sometimes it just needs to be lubed or the Brushes need replacing.

GTStinger · #7 03-14-2014, 04:01 PM

Are you near Richmond? Chesterfield Auto Parts had a 300 CD and a 300 D in it last week.

barry12345 · #8 03-14-2014, 05:57 PM

Sometimes the contact resistance is too high and the fuses holder heats. A soldered in in pigtail fuse holder will probably suffice.

It has been done before I believe. It is almost always the blower circuit that is involved with these cars in this way.

ROLLGUY · #9 03-15-2014, 12:31 AM

Quote:

Originally Posted by barry12345

Sometimes the contact resistance is too high and the fuses holder heats. A soldered in in pigtail fuse holder will probably suffice.

It has been done before I believe. It is almost always the blower circuit that is involved with these cars in this way.

Agreed, that is the best way. Even if you could get the fuse panel used, it is a nightmare to replace it.

jay_bob · #10 03-15-2014, 08:54 AM

I would do the following:

First fix your blower motor. Chances are the reason the fuse is overheating is that you have bad bearings in the motor and it is dragging. If your motor is shot there is a fix out there using a new Volvo blower motor. It's the same Bosch motor but cheaper than the one MBZ sells.

Second did you confirm that car uses a 25 A fuse for the blower? IIRC the 123s use a 16 A fuse and the 124s originally used a 25 A fuse in the box, later replaced by an external 30 A strip fuse.

Swapping the fuse box is not the end of the world. The fuse box wire harness has enough slack that you can remove the bolts securing the box to the firewall and push it back into the opening. (Disconnect the battery first!) Then go up under the dash and pull it down to the floor board. Then it is just a matter of transferring the wires over. To make that easier, get some zip ties and put a zip tie around each group of wires at a screw. Then write the fuse # and inner or outer on the tail of the zip tie. This keeps things together so you know where all the wires go.

A couple ways to fix this.

If you have an unused fuse in the box (my 240D had #5 listed as spare in the fuse card and had no wires going to it) you can transfer the wires on the back from #8 to #5. Double check that there are no internal bus connections within the fuse clip you want to use embedded in the plastic frame of the fuse box. I did this on my 240D.

Or you can obtain a 15 A ATC fuse and pigtail holder. Crimp some ring terminals on the ends of the wires and attach them to the terminals behind fuse #8.

Or you can search yards and find the external fuse holder from a 124. Open up the fuse box and detach it from the back of fuse 12. Most importantly, change that strip fuse to a 16 A fuse before using it.

MagicBus · #11 03-15-2014, 10:18 AM

Quote:

Originally Posted by jay_bob

I would do the following:

First fix your blower motor. Chances are the reason the fuse is overheating is that you have bad bearings in the motor and it is dragging. If your motor is shot there is a fix out there using a new Volvo blower motor. It's the same Bosch motor but cheaper than the one MBZ sells.

This is intriguing. I did a search and found nothing. Any chance you can provide a link to info on using that Volvo blower motor?

barry12345 · #12 03-15-2014, 11:14 AM

If the blower motor seems to sound and run normal. I would insert an ammeter into the line and check the draw before changing it out.

Many are bad and draw too much current. Still the original fuse holder setup is marginal as well. With age and use contact resistance at the fuse contacts can increase. This is what melts the plastic. If the amp draw is too high it just makes too much heat at those points. Or those resistance points increasing will do much the same. Probably only slower.