if you dont wanna read all that...the basic question is it necessary? what is it for? Ive been told it might be for an aftermarket stereo but i dunno it comes off the battery termal from the wire that goes to the starter. its just places between the battery and the starter...i think thats what the wire goes to. Im a novice


The other day i took my battery out to try and put it in another car as it had sat forever and i wasnt sure if the battery was bad or not so I used the one from my volvo. anyways...

I put it back in and i tried to turn the car on. and nothing. the rpm meter would move a bit when i turn the car on but no dash lights..nothing. I walked to my parents house luckily it was close, came back with some tools and realized i couldnt fix the wire connection so i got a new negative to ground cable. while i was gone to get the new cable i left the keys on in the car. when i got back i hooked up the new cable and nothing. thought maybe i drained the battery. so i got my a jump and it worked. so i went home and hooked up the trickle charger, it gave a reading that the battery was full.

The i took off the cables and cleaned all the connections put em back on and then replaced one of the smaller wires hooked to the battery. i believe it goes to the starter. go to turn it on. it starts! yay problem fixed right? well no. i took my roommate to the store to get some smokes and got home. thought id try to start it again. and it wouldnt start. the dash lights were dim. so i moved the cables around and sometimes they'd get brighter but never could get it turn over. definitely a short. so Ive narrowed it down to either where the cables connect to engine or there is this 20amp fuse off the battery that i cant seem to find what its for. a friend stopped by last night and he said it might be from when someone installed a stereo? its connected to the cable that goes to the starter. then feeds into a sheeth.

so i took out the fuse and connected the wires and it works. so what im wondering is do i need that fuse? or is it for the stereo? i dont wanna be driving it and have it be damaged somehow because i was driving without the fuse. Ive asked around and searched high and low and cant find any info on what its for and if i need it. God that was long winded. sorry. the thing is im not 100% that i fixed the problem yes its working now but i got it worked several timse before just to have it do the same thing. it was definitely a short somewhere i think i got it but like i said im a lil worried bout having that fuse got and just doin a direct.

here is a picture of my battery area. you can see where i connected the two wires (smallest red one to the left of the picture) there where the electrical tape is (kinda hard to see because of the hose). thats where the fuse was connected.

 

you don't say what model/year car you have...

on a 240 most years, there's a 25A blade fuse right near the battery plus terminal which provides the power for the LH fuel injection system (on the final year, some cars, this was replaced with a 4-fuse holder). on 740/940's, this fuse is in the main fuse panel behind the ashtray...

The original 240 fuse holder was white plastic, but these deteriorate with age and crumble, its quite common to replace it with a fuse holder like you showed. I usually use the marine waterproof ones, which I pack full of silicone dielectric grease.

here's the OE fuse holder (forget the guys scribblings, its the offwhite thing upper left above his hand...)


and this is the sort of marine fuse holder I've replaced those with...

 

Really appreciate you getting back to me. pretty much everyone i talked to (non volvo people) were telling me that the fuse has to be a leftover from a stereo system someone installed but that didnt quite make sense to me because it wasnt actually goin to any stereo it was connecting into existing battery cables. That totally makes sense its goin to the fuel injection. I have gone on lil drives up to the grocery store and back a couple times without the fuse connected since. I isolated my problem to be something in the fuse or connections to it. either way it was toast.

is it going to be detrimental to the care to drive without the fuse?

Obviously i need to get that in there, which by the way can you point me to a place to buy the fuse. where can i buy the fuse holder you posted? does it have a specific name or whatever if i go to the parts store to ask for it? is it possible for me to get the wrong kind. I would assume that any 25 amp fuse (and holder as long as its spliced in) should be good enough but then my assumption could be wrong and its better to ask. as they say there are no dumb questions

 

you can get a generic 25A fuse holder at any local auto parts store for just a couple bucks, should come with long enough wires to splice it in. I usually use the waterproof ones they sell at the marine/boating stores (West Marine, etc). Squirt a bunch of dielectric grease on the pins of the fuse to keep out future corrosion. put a spade lug big enough to go around the nut on the battery + clamp, and use the right size inline crimp on the harness side, I put dielectric grease in those, too... or solder it (small butane blowtorch, and rosin core solder), then paint with 'liquid electric tape' and shrinkwrap tubing.