Hello, new here, trying to get my late partner's LPG'd 2004 LS430 back on the road after about 2 years sat on the driveway. Friend of a friend came and sorted the most obvious problems, but when MOT day rolled round (mostly to check if there's any big work/welding needed rather than actually expecting it to pass) it was -7 and I discovered that the heater wasn't working, so had to cancel as I couldn't get it demisted just by wiping it. Checked stuff like lights previously but not that. It's warmed up enough now that I could probably get it to the MOT place without a heater but I'd be happier if it was working, especially as my arms aren't long enough to wipe that much window while driving if it does start to fog.
Today it finally stopped raining long enough for me to go outside and check the fuses. I've never seen the square type of fuses before, but assuming you're supposed to be able to see if they've gone by looking through their tops, they all seem fine. #1 in the long thin fuse box towards the back was sticking up a bit, so I pushed it back into place, reconnected the battery and started the car up hoping the issue was that simple. It wasn't. I had the engine running for several minutes while I faffed around poking things on the climate section of the screen trying to get something to happen. When I press the FRONT button to the right of the screen it lights up and sometimes it makes a noise like a hoover starting up (but much quieter) for a second or so then after a bit the light goes out. If I press the OFF button with a fan on it, sometimes if I then go into Climate and press HI or press the FRONT button again, it'll make that noise again. Sometimes it doesn't. ONCE it blew merrily for all of about a second and then went off again. No matter what I pressed, I couldn't get it to do that again.
Presumably if it was a fuse it wouldn't do anything at all, but car electrics are a terrifying mystery to me, doubly so when there's what looks like eleventy million wires, all black. Is it likely to be a dodgy wire somewhere? Something that's damp and not happy about it? Something full of leaves? Some consumable I've not thought of which needs changing? A problem somewhere else entirely that I would never guess is related? Any hints you can give would be appreciated (especially if they don't involve buying a multimeter).