No connection between AC switches and AC relay

[francesconyc]

After and extensive troubleshooting of my AC, testing the components separately, I discovered that I have no power coming into the cabin, between the red wire (C) to the AC relay (87). Testing ohms with a multimeter it seems I have no continuity.

the relay works (tested) so I'm down to think it can be a relay socket plug defective (or the wires behind it. maybe simply the female socket is loose...who knows

Does anyone ever have an issue with these sockets? how to replace it?

is this correct?

In the worst scenario, I was thinking that I could try to buy this new socket and connect a brand new wire through the firewall and hack my way to provide power to the AC...

[kuehl]

The primary AC relay in the smuggler's box?


That would be a relay with 1/4 male spades, not round pins.
Commonly called a 5 pin (spade) SPDT 12v relay.
The "socket" it plugs into is common; findable in brick and moto parts stars.
Just bring your relay in with you.

Factory schematic shows 2.5 mm wire, so 14 awg should handle the load.

[francesconyc]

Originally Posted by kuehl

The primary AC relay in the smuggler's box?

no, the main Ac relay in the fuse panel that brings power to the switches THEN to the smuggler box etc

[kuehl]

If you want to bring power to the AC related 'switches', such as thermostat switch and 3 speed evaporator motor switch:

You start at the battery, wire it to the fuse panel, tap off of fuse #2 (closest to the windshield), send power from it to primary AC relay in the smuggler's box, and from there to the AC Evap fan speed switch

If you want to send power to the Front Condenser Blower Motor Relay (aka "Cooing Fan Motor AC Relay) then you'd run a another tap off of fuse #2 to it it.
This relay is tripped on when the thermostat contacts close.

[kuehl]

not verified but this is close enough

[wazzz]

I think there might have been some confusion between the two relays right from the beginning.

Francesco has been trying to check continuity between terminal C of AC switch (plain red 2.5mm wire) and terminal 87 of condenser fan relay instead of main AC relay in the evap compartment. Hence the failing test.

[kuehl]

I'm sorry, my mistake.

[francesconyc]

Correct.

Today I did another test. I connected a motorcycle 12V 7ah battery to the front motor (next to the spare wheel/jack) and it didn't work. I guess the motor is dead? will deinstall it tonight when I have more time and bench-test it. and then I guess will buy the Griffit fan+motor combo...



btw I did a test for continuity between the main AC relay and that fan and it's all good.

Remains the mystery of the missing continuity between the main AC relay and the switch in cabin that powers everything essentially.

So I also unscrewed the fuse panel and checked the relay socket, and I saw this in the photo. The socket has two black wires, one go to the front fan, a wire or two go to the fuse, the other wires (hard to follow where they go) go in the cabin.




Is it normal this socket is fixed with some electrical tape? I wonder if the culprit is just in this

[wazzz]

Please read post 6 above and Kuehl's posts further up.
It appears that since the beginning you are confusing the main AC relay, which is a square relay located inside the smugglers box, and the condenser fan relay, which is the round relay in the fuse box. You were trying to find continuity between two points that are actually not connected to one another.

So now you need to test continuity between C terminal on AC switch and terminal 87 of the square relay inside smuggler box and not terminal 87 of round relay in fuse box.

[francesconyc]

oh god. I think I got confused by the Bentley diagram they call AC relay, the round relay, also the plastic cover on the fuse panel call it AC relay, so I thought that was the main relay....

so the round relay is ONLY for the front cooling motor, now I see makes sense the wiring I took pic of.

I will test again tonight.

but I guess my front motor is dead right? is not about amperage right?

[GH85Carrera]

Originally Posted by francesconyc

oh god. I think I got confused by the Bentley diagram they call AC relay, the round relay, also the plastic cover on the fuse panel call it AC relay, so I thought that was the main relay....

so the round relay is ONLY for the front cooling motor, now I see makes sense the wiring I took pic of.

I will test again tonight.

but I guess my front motor is dead right? is not about amperage right?

That front condenser fan was NOT fused from the factory. If you replace it, be sure to add in a fuse to the fan. It caused more than a few 911s to burn up.

And as many have said, the main AC relay is a square relay on the side of the "smuggler box" where the main evaporator blower is.

[francesconyc]

Originally Posted by GH85Carrera

That front condenser fan was NOT fused from the factory. If you replace it, be sure to add in a fuse to the fan. It caused more than a few 911s to burn up.

And as many have said, the main AC relay is a square relay on the side of the "smuggler box" where the main evaporator blower is.

yep, the Griffiths motor comes with all I need...
https://griffiths.com/product/porsche-911-930-front-condenser-motor-and-blower/

[GH85Carrera]

Likely your housing is like mine, and the plastic is very brittle. Be careful removing it, and removing the clips open the housing up, as the plastic is very easy to break.

[kuehl]

Easy to get confused when you are workin in the Frunk

[wazzz]

Actually condenser fan is fused by the 25A fuse that also feeds other lines. But I guess a 25A fuse is too big to protect from overcurrent caused by a binding condenser fan.

So what would be a good value for an inline fuse put upstream the fan alone? 8A? 10A?

[francesconyc]

Originally Posted by GH85Carrera

Likely your housing is like mine, and the plastic is very brittle. Be careful removing it, and removing the clips open the housing up, as the plastic is very easy to break.

thanks for the heads up!

[kuehl]

Originally Posted by wazzz

So what would be a good value for an inline fuse put upstream the fan alone? 8A? 10A?

Well, the front condenser blower housing melts when the fan motor shorts.
That is because there is not a fuse between the frunk condenser fan relay and the fan motor. So, I'm guessing, around 89 they fused the motor.

We supply the plug inline fan fuse assembly with 7.5 amp fuse with our Front Condenser Fan motor with Blower Wheel; alone with base housing gasket
material and a few washers for those broken housing corners, and instructions.

https://griffiths.com/product/porsche-911-930-front-condenser-motor-and-blower/

[francesconyc]

ok some updates. I think I found the culprit or culprits...

In the smuggler box, I finally untangled and removed a lot of black electrical tape that was hiding a nest of wires...I found some interesting odd things:

2 black connectors holding a fuse inside (one of those was actually empty!), going to/from fuse #20
I'm not sure why they added extra fuses here between the square relay and the fuse...

then I also found this sort of relay/fuse looks like a WWII component ( I googled it and it is a "Thermally actuated snap action device"...was this a Porsche component??) between one of the square relay pins (didn't check the number)

Now... question is... should I just bypass all these fuses, to return the wiring to the original diagram or or keep them? I'm not sure if they are meant to protect the evaporator motor or whatnot
I was told the PO did some work, so I wonder if these extra fuses were here to prevent something...


in this case, if I keep them, what AMPerage should I use here?

see pictures

[francesconyc]

...and I just ordered the https://griffiths.com/ front motor... it was SO DEAD...

[francesconyc]

I think we are close to solving the mystery.
what I tested so far

- ordered new fuses for the wire "jungle"
- removed the thermo whatever switch
- waiting for brand new front motor