Just a coincidence; item 21 in the the workshop manual section/page I10 (A/C) is the "hidden fuse". While item 21 in the wiring diagram is the three wire connector (brown/black). . Image Unavailable, Please Login
Here is my project completed. The wire was thick brown wire. Not a lot of extra wiring available so take care to snip the wires as close to the old fuse as possible. I have tested this and seems to work really well - I cannot feel any heating around the new fuse which should indicate that we have a good current transfer from wiring to fuse. Image Unavailable, Please Login
That's good to know and you certainly caught yours early enough. Currently, my brown/black wire connector measures above 200F within 5 minutes of operation so I need to replace it as well.
My A/C isn't cooling so I checked the fuse, thanks to this reminder. My problem is not the fuse, but the holder is toast just as depicted in the OP's pic, so it needs to be replaced anyway. Not only that, the brown wire between the fuse holder and the relay shown in the background of the pic has cracked and missing insulation. I have some brown wire of the correct gauge but I can't figure out how to remove the terminal from the relay plug so I can replace the wire. Most of the time there's a tab on the back of the terminal that can be depressed with a pick, allowing the terminal to slide out of the plug, but that hasn't worked for me so far. Can someone who has removed a terminal from one of those plugs tell me how to do it so I don't screw up the plastic plug? Probably ought to start a new thread for this but it would be better for the archives if that info was included here. TIA for any tips!
Important: do not put higher Amp fuse as the overheating and melting is not related to the original fuse amperage rating. Bigger fuse but still 30 Amps is the correct solution. The fuse is designed to safely melt (blow) if there is a problem in the system. Higher Amp fuse may cause some other point, or length of wire, in the wiring to become the weakest point which will not safely burn but burn rather spectacularly (smoke and fire). The AC fuse and its surroundings melt because the relatively small contact areas of the fuse pins, after some corrosion over time, develop resistance which attracts heat build-up (become powerful heaters). A large audio fuse or Maxi spade fuse is the solution. I used a 30 Amp Maxi fuse with new 9.5 mm (3/8 in.) good quality spade connectors which plug in really tight. Image Unavailable, Please Login Image Unavailable, Please Login
Answering my own question, I couldn't resist giving it one more try and found that there is a square hole on the back side of the terminal and a corresponding square tab on the inside of the plastic plug housing. In order to remove the terminal you must flex the plastic plug housing to the point where the square tab pops out of the hole in the terminal. A straight pick tool worked great for this. Hopefully this will help someone in the future. A big thanks to the OP and othe contributors for all the great info on what is apparently a common problem.
Hi Mike, Grate you found the way to pull the spade out of the block. If you cannot find a new spade which will lock in position inside the block, you can always cut/trim the block around where the brown wire connects to the relay and plug the new spade separately to the relay pin. It is important to make sure the new spade plugs in really tight to the relay pin otherwise this point will become a new "heater".
Another possible upgrade at the AC fuse is a stronger relay with bigger (9.5 mm) pins 30 and 87 (where the thick wires connect). It is Volvo again, p/n 9441158. The relay is otherwise the same size as the original. Image Unavailable, Please Login
