1983 5.0L A/C Compressor harness diode

[bigdedition]

Hi All,

I have what I believe is an Engine from a 1983 T-Bird, 5.0 in my 85 Mustand LX i just acquired. Regarding the A/C Compressor harness on mine has a diode on it, is that normal for T-Birds? I can't see to find that part, only the connector to the compressor.

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[74 Harley]

Can you post a picture?

 

[bigdedition]

 

[74 Harley]

That's probably part of a low pressure cut off switch. Diodes are normally only found in the alternator.
My best response is to get a wiring diagram for your car and an underhood harness. It can be very difficult to try and swap harnesses between cars since not everything is always in the same place. Different model years may also have different connectors.

 

[Tom Alpers]

They put them on some cars to prevent an EMF backflow when the clutch was turned off. The clutch is a big coil, just like an ignition coil, and when the current thru it stops it creates a large "power" surge, ie. EMF pulse, which travels "backwards" on the feed wires. I don't know why it was a problem on some cars and not others, but I know for sure it was a big enough problem on some GM cars they put out a service bulletin to install the diode. I assume that Mustang has one on it for the same reason. It's the same reason some of the bosch style relays have an internal diode on the coil.

 

[bigdedition]

They put them on some cars to prevent an EMF backflow when the clutch was turned off. The clutch is a big coil, just like an ignition coil, and when the current thru it stops it creates a large "power" surge, ie. EMF pulse, which travels "backwards" on the feed wires. I don't know why it was a problem on some cars and not others, but I know for sure it was a big enough problem on some GM cars they put out a service bulletin to install the diode. I assume that Mustang has one on it for the same reason. It's the same reason some of the bosch style relays have an internal diode on the coil.

I was reading the same, seems like some of the Mustangs had Diodes for the A/C clutch. I have a feeling this was from the harness from the V6 Ford engine but I don't see that I can order it for my year car. I found some on eBay but existing wires are fraid just like mine. I found a new harness kit for 86+ model Mustangs so I ordered it and will just modify the ends to work with the T-Bird engine. If it's required or not it's an additional safety mechanism if anything, now that I have a better understanding thanks to you all.

 

[ak7an]

If you are needing to replace it, you could just use a 1n4001 diode in its place and just use shrink tube around it. Remember that diodes are polarity sensitive, so make sure and get it in correctly.
Take care
Ed

 

[bigdedition]

If you are needing to replace it, you could just use a 1n4001 diode in its place and just use shrink tube around it. Remember that diodes are polarity sensitive, so make sure and get it in correctly.
Take care
Ed

Yep, it is the polarity direction on the outside of it so I will just follow the same suite.