no power on accy

PS - I had assumed that the fuse was ok and had blown again. Ween questioned the fuse status a few times, and that's where I butted in with my common tip. [Fuses are usually the first check. However many fuses seem to be ok but aren't, hence my experienced learning where I always ROTATE fuses AS WELL as checking the fuse(s).] But in your 2nd last reply, you didn't measure the downstream side voltage (which should always equal the upstream side of the fuse, though if that's 0V, then it is not getting power...). If it's a one-off blow, then no big deal. It's if it reoccurs that all the writing in this thread should be useful. It it is a one off, then this should be 3 post thread - no power; check fuses; 40A fuse blow - thanks! And do not take the last sentence as any form of sarcasm. This forum is to help people and that includes people that know nothing about cars or electrics or that fuses exist etc. And boy oh boy, even I have had multi-pagers for threads that should have been 3 post threads!

LOL yeah I know what you mean, Oldspark. My Alarm thread was like 17 pages long! Haha! I still go back in there to recap everything I did. Good info around here! Anyways, I took apart the blower motor and the entire thing was seized up. It took a lot of force to turn it. The connector to the wiring harness was starting to melt also. Yes, potentially dangerous. I tested the resistor as well and it was out of spec, so I'll need to replace that as well. Thanks again for that circuit diagram. I now have a clear understanding of how this works!

Thanks. Diagrams can be hard to find. Sometimes I search and find paysites etc but might persevere and eventully strike a brilliant site. (A recent search to get some info for my brother's mate's RX7 found a site with all(?) RX7 models and their Manuals downloads - mechanical and electrical, all year models.) Glad you found the problem. Glad too it was a possibility predicted by someone... Yeah, this is a good site eh?! Hopefully this is another example how problems must be stepped thru in a logical order, but I suspect you figured that out once you had the diagram etc. (And never assume good GNDs or fuses or even battery connections...) Alas my replies tend to be long because I foremention the possibilities up front. That's bad from a confustigation point of view. Ween OTHR took more of a step by step approach ( - cum elimination) which is the proper way to do things though it can mean many small replies & iterations, but that usually less confusing (maybe with the expense of more replies). Happy accessorizing! PS - BTW - seized or seizing motors are often a cause for over-currents and fuse blowing etc. So too worn motor brushes. (But NOT air-blocked fans etc - they normally reduce current!) Glad the fuse blew before the connectors etc melted and started a fire, or smoked occupants to death. (READ: Glad nobody uprated the fuse to a 2-inch nail etc!) Again, that is a good example of my suggestion to check wire & connector and switch warmth on occasions as a preventative maintenance measure, or as a tool to finding problems.    It's also a good example of when - or why - not to uprate fuses etc. Check the condition of the melted wires and contacts. Contacts can lose elasticity or corrode and hence heat up and flame etc. (Such faults do not always blow fuses. In fact like arcing faults, rarely do the fuses blow.) Some warm or bad contacts an simply be fixed by breaking and making the contact to break thru contaminants etc - ie, disconnect and reconnect all contacts. (That's why some fuse checks fix problems - the remove & refit is the fix - and novice fixers are left totally confused as to how they fixed it. Else witnesses think us repairers have spiritual powers.)