no power on accy

is fuse #25 (40A) underhood ok? that fuse feeds both the blower motor (IG2-B) and accessory (ACC) circuits through the ignition switch .

Interesting. I see that in the schematic I have but I can't locate that fuse in the underhood fuse box! It's not even labled on the fuse box.  How strange...

EDIT: Actually #25 is under dash. I just replaced it. No dice.

did the fuse have power present on one of the terminals for it? one side should be battery power, the other dead. test the dead side for continuity to the ignition switch. test the blue/white at the blower motor for power...key on of course. ground the blue/black at the blower motor with a jumper lead, does the motor spin?

I went through the flow chart as described in the service manual. No 12v to the blue/white at the blower motor. I also tested for 12v at the solder joint on the ignition switch itself which didn't show any output.

so assuming we are looking at the same manual/diagram, you have no power on IG2-B nor ACC. is there power at BAT-B? if no, is there power at the No. 25 fuse? if there is and not at BAT-B, you need to test for continuity between the non-powered terminal of fuse 25 and BAT-B. of course, make sure the fuse is good also.

I'd suggest my normal fault finding technique - ROTATE all same rated and type fuses. If a single non-matched fuse, then replace (rotate) with a spare. Then try circuit tracing etc.

In response to concerns raised by another esteemed the12volt contributor... I've briefly looked at a basic diagram ( autowiringmanual-199093-honda-integraacura-integra-wiring-diagram). That shows the ACC being on the same "Bat-B" IGN-switch circuit as the Blu-Wht IG2-B circuit which I take as being the heater. (The other IG-switch Bat-A circuit is Wht-Blk circuit via 50A Fuse #32 and is for IG2-A, IG & STart.) That ACC circuit is from the Wht-Red power via 40A fuse #25. If the IGsw solder joint for the ACC is NOT +12V with the key in the ACC position AND an intact 40A fuse #25 (ie, +12V at the Wht-Red solder joint), then that switch is faulty (burnt out else worn) in which case the Blu-Wht IG2-B joint for the heater will not be +12V in the IGN position. If burnt out, the question is what burnt out the switch? A 40A fuse or circuit breaker could be wired direct from the battery to test the Blu-Wht IG2-B heater operation. If that blows, then there s a heater fault. That circuit could be disconnected until the fault is found. But it may be mere age that has blown that switch contact. Contact surface contamination increase resistance over time, hence heat and eventual destruction. Personally I don't like any switch to carry more than a few Amps. I have removed many such loads from my OEM (1965 vintage) switching via relays (eg, IGN via a relay, full current carrying headlight switches & dippers switch relays instead, etc).    Heater problems may be a shorted motor, or motor speed dropping resistors (usually wire coils in the fan path) shorting to GND. It may also be a high ACC loading or a short that has caused switch burn out. In both cases, the 40A fuse should blow. But repetitive replacement or use of a higher rated fuse could have cause IGsw damage. (As well as the aforementioned "high current" and age issues. I often feel for switch and connector heat to ascertain their health. But be warned - burns are not uncommon!) Another aging or "current overrating" consideration is connector elasticity - ie, fuse terminals and female contacts can be heat effected and lose contact pressure. Both male & female connectors can lose conductivity due to heat effects. The above is a somewhat limited reply. I don't have the complete wiring diagram (my torrent is slow...) but wanted to add some considerations or tests before a new switch was fitted etc as well as suggest a testing order. Otherwise your testing method seems fine - especially now that I know what circuits you and Ween are referring to. FYI - I was concerned about the somewhat large 40A fuse for ACC, but now I know that is fine. (Not that I know the vehicle's history - ie, when problems occurred, and if anyone has used a 2" nail (>40A fuse) for that circuit.)   

Thanks guys. I'll check ASAP. I know I measured one side of #25 fuse and it did have 12v. I didn't bother checking the other side :(

Oldspark! The 40a fuse IS blown! I'm going to wire the heater fan/blower directly to 12v and see if it turns and continue to follow the troubleshooting flowchart in the factory service manual. Thanks!!

To help find a short, instead of blowing fuses (if you don't have a circuit breaker), you can use a light bulb in place if the fuse. While the short or heavy load exists, the bulb lights. A big bulb (eg, headlight - with due care handling halogen bulbs if relevant) will only light for heavier loads or shorts (above a few Amps). That's a very useful technique for intermittent faults - the bulb lights when the short occurs, eg with suitable switch positions; jiggling wires; or vibration and bumps. [ Circuit-wise that's like 2 series resistors. The bulb is the first and lights if the 2nd (the load or short) is of similar or lower resistance, and it limits current to the bulb current - eg, if there is a short to GND, the bulb is "powered normally" from 12V. No loads or light loads likewise limit the current thru the bulb, hence it's dim or off.] Other than judging brightness levels etc, it doesn't show what the actual load or fault current is. That requires a big ammeter or for large currents above a DMM's normal 10A limit, a shunt and voltmeter. The bulb can act as a shunt (though halogen bulbs are quite non-linear wrt voltage versus resistance).