Radiator fan & A/C not working~any help appreciated

[okehdokeh]

I pulled the BSI out and popped the cover off the back, from the diagram attached I bridged terminals 4 & 5 on the relay and although I got a very small arc when the bridge made contact on the relay pins with or without the A/C button pressed (ignition on without engine running and with engine running) I had no clunk from the clutch engaging. Do you think this is a suspect relay or the fault lies elsewhere maybe? Thanks.

RELAY.JPG

[Doggy]

That is puzzling.
I note you previously said that applying power directly to the clutch connector caused it to pull in and the a/c worked.
Since you saw a spark when bridging the terminals it looks like you have power to the relay.
Odd that it doesn't operate the clutch.

I would check the following:

1. You have +12V at either pin 4 or 5 of the relay with the ignition on, (may possibly need the engine running).
2. You have continuity between the relay pin that is not at +12V and one pin of the clutch connector.
3. The other pin of the clutch connector is connected to ground.

[okehdokeh]

Ok so I have 12v+ at pin 4 with or without ignition on and continuity between pin 5 (not 12v+)and the green and yellow wire at the clutch connector which also has continuity to ground. The other wire which is grey at clutch connector has no 12V+ or continuity to ground with either ignition on or engine running.

Could it be that the grey wire at the clutch connector should become live from the second #4pin going clockwise on my diagram, this pin is not 12v+ although the third #4 pin going clockwise on my diagram is. Proper confused now I am

[Doggy]

I'm struggling to relate the diagram to the relay, (it could be a mirror image of the diagram). Are there any numbers on/near the pins?

If you measure at the terminals of the spare relay,
- all the no.4's should be connected together,
- the no. 5 shouldn't be connected to anything unless the relay is closed
- measuring between the 2 coil connections should read somewhere between a few hundred to a few thousand ohms, (at least in one polarity as it may have as diode across it).

I had assumed that the relay would switch a +12V supply to one side of the clutch and the other side would be connected to ground, but it is equally possible that there is a permanent +12V supply to the clutch and the relay connects the other side of the clutch to ground.

(Unfortunately I no longer have access to the diagrams so can't tell you which of the above is correct, but one of them has to be).

[okehdokeh]

Hi Doggy, yep all three #4 pins are connected and #5 not. On the Tyco spare relay the resistance is around 90ohms on the 200ohm setting on the meter as is a standard 45/30 relay on the same meter setting.

I'm thinking that there should be a permanent live at the clutch like you suggest probably fed from the circled 2nd #4 pin on the picture I have attached to this post. The relay would make the circuit to earth to engage the clutch then.

There are no numbers on the Tyco relay itself which doesn't help if I wanted to piggy back a standard 45/30 relay off of it.

[Doggy]

I think what you're saying means the 3 x No.4 pins on your spare relay are connected together, but they cannot be on the relay in the BSI.

Earlier you said the pin marked "No 12V+" was connected to the clutch wiring plug. It follows that if this pin was internally connected to the other No. 4 pins it would also be at +12V.

I would be tempted to connect +12V to this pin, (ideally via a fuse), to see if the clutch then pulls in

[okehdokeh]

Sorry for the late reply but I have now got working A/C. I wanted to say thanks to the help on this forum I managed to understand things a little better and despite not having the pp2000 set up got a positive result.

After taking the advice of Doggy, bridging the terminals on the BSI relay and getting an arc made me think that the relay was ok, the second #4 terminal on the BSI relay that I thought was dead turned out to be ok, I scratched at it real hard with the meter probe and got 12v+, my fault for not doing it right first time!

Knowing the pressure sensor was new and ok and the independent power to the A/C clutch which actuated it and gave me cold air at the vents and kicked the fan in low speed suggested the problem lay between the BSI and the compressor, probably the BSM I thought.

I traced the grey 12v+ feed up from the A/C clutch to the BSM and found there was no power at its pin on the multi pin connector despite the BSM #1 10amp fuse that feeds that pin being live and not blown. Now thanks to another of Doggys posts I popped a paper clip into the BSM connecter just where the grey power feed wire to the clutch was, wired the paper clip with an in line 10amp fuse to the battery and started the engine.

The A/C clutch was now engaged with the engine running and I left it like that for about 2-3 minutes, after this period of time I left the engine running but removed the jump wire from the battery to BSM and the A/C clutch disengaged. With engine still running I pressed the A/C button on the centre console and the A/C clutch engaged on its own, repeatedly pressing the button turned the A/C on and off as normal. Whoo hoo!

A round trip from Leicester to Tamworth and back again and the A/C is still working although the wife complained she was too cold and put the heating on 23 degrees .

Like Doggys issue I can only assume the new pressure sensor needed to read more pressure in the system before telling the ECU things were tickety boo!

Anyway thank you again for the wisdom you shared and stopping me from going mad, THANK YOU.

[Doggy]

You're welcome, well done getting to the bottom of it.

Thinking about it, it's likely your sensor was the problem and that after replacing it you needed to force the clutch to operate the first time, much as I had to after swapping my condenser many moons ago. (It wouldn't have 'seen' your gas pressure).

[okehdokeh]

Your post on the condenser swap was the one that got me there Doggy, very much appreciated sir. It's the bits of information like that that are worth their weight in gold
I intend to keep the car for as long as I can so pp2000 is a must I know, I will look around for the best deal on the kit.

Thanks again