1981 300SD blows climate control fuse - PeachParts Mercedes-Benz Forum

Elliott Fager · #1 11-05-2002, 06:36 PM

Would anyone happen to have any ideas why my 300SD is blowing the 8 amp climate control fuse? Strangly, it seems to happen when I hit the higher rpms while accelerating during freeway merging or getting out of a tight spot in traffic. I average about 1 fuse every week or so---wish I was a bit more electrically minded. Thanks in advance for your thoughts on the matter

MikeL · #2 11-06-2002, 12:17 PM

is that the same fuse which powers the horn, the ac radiator fan, and the small heater circulation motor?? The same exact thing is happening to me..1984 300cdt

Was going to unplug everything and slowly add stuff back into the circuit until I could identify the source but that could take weeks.

MikeL

dieseldaddy · #3 11-06-2002, 01:19 PM

Here is a voice of experience.
I had the same problems in my 300TDT this summer.
I had gone through and replaced all the fuses according to the little paper inside the fuse box cover.
Well, after searching for hours on this forum, I learned that there was actually a correction and that the 8a fuse should really be 16a.
8a would blow in about 30 seconds...
I have not had the 16a blow since and everything is fine.
There is a ton of threads on this subject. I will try to find the one(s) that convinced me and post it here.
---------------------
Edit:
Here is my original post but I could not take the time (at work now) to find teh actual one that swayed me.
HVAC Fuse Blows...

Elliott Fager · #4 11-06-2002, 01:33 PM

Thanks Dieseldaddy,

The fuse issue is causing me to blow a fuse! I wasn't aware that Mercedes recommended changing it to a 16a

Elliott Fager · #5 11-06-2002, 01:41 PM

Thanks Dieseldaddy,

The fuse issue is causing me to blow a fuse! I wasn't aware that Mercedes recommended changing it to a 16a

dieseldaddy · #6 11-06-2002, 01:43 PM

Correction: In re-reading my last post, my fuse was SUPPOSED to be 16a, but MB recommends replacing with a 25a.

since my 300TDT is a 1981, and YOUR SD is a 1981, I am making a giant leap in assuming that this *could* be your problem as well... In my tiny little mind, replacing a smaller blown fuse with a bigger new one is only masking the problem, but if MB suggests it, I would believe it!

Good luck.

Joe Blowe · #7 11-06-2002, 07:16 PM

dieseldaddy,

i remember reading that thread of yours, as i was going through the same thing at the time.

i never did find an official MB TSB that suggested the 16 or 25 amp upgrade. would you happen to have a link to such a notice?

like you, i did run across several people that stated it as fact though...

Joe Blowe · #8 11-06-2002, 09:31 PM

hey txbill,

from that same thread:

Quote:

Originally posted by TXBill
I believe the 25 amp fuse is correct, as per a Mercedes TSB on that subject. I got this information from a Mercedes tech when I was visiting at my favorite Houston dealership, Star Motorcars. If Gillybenztech or Aaron Greenberg see this thread they could confirm.

so, is there really a TSB? and by the way, i never made the leap to installing a 25 amp fuse...

Joe Blowe · #9 11-06-2002, 09:38 PM

the number 8 slot actually holds an 8 amp fuse. that's why i was hesitant to drop in a 25 amp fuse.

quite a jump

but if you're saying that an MB mechanic gave you the go-ahead, that's good enough for me.

Eric Eliel · #10 11-07-2002, 12:59 AM

My 84 300D did the same thing. Check the kickdown switch wire leading from the transmission up to the inside of the car. My leaking trans. (410,000) had eaten the plastic electrical wire jacket and the wire was shorting against the frame. Whenever I engaged the kickdown switch the fuse would ground and blow. I just cut the wire, spliced it and used a wire nut. Not pretty but that was a year ago and it stil works.

Elliott Fager · #11 11-07-2002, 09:19 AM

There might be some misunderstanding in my original question---The fuse that is blowing is the #10 fuse on a 300SD. That fuse is an 8 amp fuse which is also connected to the rear back up lights. (maybe more stuff too) If memory serves me correctly, I also replaced the elect. fan fuse with the 25 amp fuse as well. Thanks for all the interest in my problem. What a great forum

Joe Blowe · #12 11-20-2002, 04:54 PM

i think i just found an article that answered my previous question:

http://www.mbca.org/MBCA_blower_fuse_kit.htm

Elliott Fager · #13 11-20-2002, 06:11 PM

Thanks for the help Joe.....I'll take a look at it tonight