So I'm troubleshooting an A/C compressor clutch not getting power and I feel like I'm going in circles with it and the FSM. It seems like the FSM isn't completely accurate, or I'm not reading it right, has anyone else run into that?

So what I have is that the condenser fan circuit appears to be working when the A/C switch is pressed, the condenser fan comes on but the radiator fan does not. The radiator fan comes on when the engine reaches temperature though. I don't have power on the Blk/Yel wire at the A/C delay Relay or the A/C clutch relay. Tracing the circuit on page 288 of the Electrical Troubleshooting Manual for the A/C Delay Relay it shows that power comes from the Fuse box off Fuse 13, goes to the radiator fan circuit from a splice, then goes through connector C201 which should be behind the blower motor. There should be 6 wires in it. I pulled the blower motor assy and there is no connector behind there. I just had a thought that maybe the connector they are talking about is the one that actually plugs into the A/C Delay Relay. The wires at the Delay Relay run straight through the firewall to the relays by the battery.

It's kind of looking like the relays by the battery are the heart of all of this and that is where the splices and connections are that connect the system. So at the relays I can find 2 Blk/Yel wires that are not jumper wires and that go into the harness back to the firewall. One will be the wire going back to the A/C Delay Relay, the other should be the power wire from the power distribution point. It's a little difficult to troubleshoot because once I put power on the Blk/Yel, all the Blk/Yel wires light up so I can't trace the source without cutting the wires to isolate the one I want which I would rather not do.

So to make a long story short, has anyone else done troubleshooting for a similar issue in this area and maybe knows where the power source comes from for the Blk/Yel at the relays by the battery?

 

Yes, you are making this more difficult than it really needs to be. If you going to reference a schematic, please provide pictures of it. You also need to tell us what size engine and if anything else was done to the vehicle wiring or A/C system, such as repairs etc.

If the compressor does not engage, start with the compressor circuit itself and work backwards until you find power. You might have a bad pressure switch etc, all of this will be revealed in a schematic diagram.

I do this for a living, https://honda-tech.com/tech-misc-15/...oesnt-2900177/

 

Thanks for the reply, the car is completely stock and is a 1.5 engine, I thought the engine size was evident from it being an 87 SI, I believe that was the only year that had the 1.5 FI engine, I could be mistaken though. So I worked forward and backwards yesterday on this, I don't think I'm making it harder than I have to but it is a challenge to trace wiring on any car. Bear in mind I was a professional mechanic for 20 years before I went into computers, I have had plenty of practice tracing wiring and understanding circuits. I don't like cutting harnesses apart to find the wires I'm looking for. Long story short, I traced enough to find the #13 fuse wire in the Rt hand harness by the battery just before the harness goes down by the bottom of the radiator. The wires going to the relays come up from the bottom of the radiator so it looks like somewhere down there I have an open or corroded wire.

I noticed in the wire diagram that the circuit at the relays is really just a group of jumpers that power all the relays. To fix the issue all I had to do was provide power on any of the Blk/Yel wires at the relay. So because I was tired of cooking in the sun and didn't want to remove the radiator and condenser to find my open, I just ran a jumper wire from the #13 fuse wire where I know I had power, to the Blk/Yel power wires to the relays. Not my preferred method of resolving the issue but it works like a champ and I know what I did for troubleshooting any issues later. Sometimes you just have to fix it as long as you do it safely. In the future when I get my garage built or have to do other maintenance in that area I can continue troubleshooting to find there my open is. In the meantime, I'm enjoying the A/C.