Topic: Second guessing the fan controller...

[Jeffy]

downside the way i see it is that you need to add more wires and reconfigure your current setup, only add 1 wire with the diode.

Yeah, I'd have to rewire it but I'm used to wiring.  I have spools of wire, connectors and such.

Is there any problems with no having a diode on the thermo switch side in the original schematic?  I haven't really thought about it.

[aka-justin]

Yeah, I'd have to rewire it but I'm used to wiring.  I have spools of wire, connectors and such.

Is there any problems with no having a diode on the thermo switch side in the original schematic?  I haven't really thought about it.

I'm paranoid.  I always diode up both sides of combined power sources. Nothing more fun then toasted wires or equipment. I'd just tie two diodes to a butt connector leading to your relay and each diode individually to each power source.

[Jeffy]

I'm paranoid.  I always diode up both sides of combined power sources. Nothing more fun then toasted wires or equipment. I'd just tie two diodes to a butt connector leading to your relay and each diode individually to each power source.

That's what I was thinking too.  I still like that diagram you did though.

[aka-justin]

Thanks

[sharpxmen]

Is there any problems with no having a diode on the thermo switch side in the original schematic?  I haven't really thought about it.

not in your setup (if its like the diagram you posted)

the diode is there to prevent the clutch engaging when the thermocouple is on, having 12v on the ouput side of the t/c when is off is not affecting anything (it has no effect). That being said adding a diode on the t/c output will not hurt anything (if that gives you some peace of mind).

[Jeffy]

Well, it looks like I'm not second guessing any longer.  I filed a depute and two days later, without a word, he send a refund.    I asked if he could give me a solid ship date and if not then I'd like to get a refund.  I didn't really expect to see an answer since I've never gotten a reply from any of my emails I've sent to him.

In any case, I'll be buying some diodes and terminals so I can trigger the fan from the AC blower switch.  I think I'll spend the $200 on the 200a Alternator instead.

[sharpxmen]

good plan, this guy has bad customer service manners.

[Jeffy]

good plan, this guy has bad customer service manners.

Yeah, I don't know how this guy stays in business.  Although, I'm sure it's not his day job.  Worked out of his house so, yeah, he's got no overhead to deal with.  It looks like his website is trying to eat itself.  No contact info listed and mediocre interactions with the internet at best.

In any case, yeah, I've got to add some splices to my AC switch so I can tell the fan and PCM to do their thing.  Also, need to get rid of the 75a (stock) alternator and go back with a high-amp one.

[Jeffy]

I'm having a brain fart...  When installing the diodes I want the Cathode (->|) towards the relay and +12v is on the Anode right?

[sharpxmen]

Getting back to the original question;  I'm having a brain fart...  When installing the diodes I want the Cathode (->|) towards the relay and +12v is on the Anode right?

the arrow should point same as the logical current flow, so would be like you say from the clutch wire (which is the power source + in this case) towards the consumer (which is the relay solenoid). the vertical bar side is the cathode (i'm a little confused by your diagram above ->| and i don't know which side you mean) and the arrow side is the Anode

so should look like this

+12v_Clutch_Wire -->|-- Relay_Solenoid
(probably that's what you meant but you see why i'm not 100% sure)

[Jeffy]

It's going to be +12v Key & A/C Blower ->| Relay.

Should be the right then?  Basically 2 +12v sources going to the trigger on the relay.

[sharpxmen]

It's going to be +12v Key & A/C Blower ->| Relay.

Should be the right then?  Basically 2 +12v sources going to the trigger on the relay.

hang on, why 12v key, that goes to the thermocouple and from there to the relay right?

so like this

  +12v_key - t/c - (-->|--) - \
                                         | - Relay
A/C_Blower_+12v- (-->|--) - /

but you could also use the A/C Compressor clutch wire as there's no need to run the fan when the compressor is off.

[Jeffy]

hang on, why 12v key, that goes to the thermocouple and from there to the relay right?

so like this

  +12v_key - t/c - (-->|--) - \
                                         | - Relay
A/C_Blower_+12v- (-->|--) - /

but you could also use the A/C Compressor clutch wire as there's no need to run the fan when the compressor is off.

My fault for not being clear.  Yes, you're right, the thermocouple goes to one lead.

The reason for having the fan on when the blower is on is so there isn't the lug when the compressor AND the fan kick on at the same time.  Although the fan isn't as noticeable now that I have the new alternator.  This is also how most cars are wired from the factory.  I might change my mind on it though.  Like you said, there isn't any reason for the fan to be running all the time but it could get annoying when the AC is on low and the clutch kicks on and off every 10 seconds.  Lots of cycles.

I need to get some more shrink tubing to finish it.

[sharpxmen]

looks good
why not just joining the 1 end that goes to the relay on the diodes and use 1 wire from there?

[Jeffy]

looks good
why not just joining the 1 end that goes to the relay on the diodes and use 1 wire from there?

I didn't even think of that.  I'd probably end up with a big clump of solder if I tried gathering them all together.  So this looks neater.  It's not a big deal though.  I was just some scrap wire that I had and there was plenty.  I have them crimped together in one terminal.  The wire is only 3.5" long on either side of the diode.  I have to wait to get some more shrink tubing though.  I seem to have run out.

I also need to figure out what size terminals are on the AC blower switch.  They're larger then the 1/4" I have.  6.3mm?