Wiring for heated rear screen - Mk1 Capri

[jimbo]

I'm fitting a heated rear screen to my Mk1 Capri...From the looks of it, there are no wires in place to support this, so it looks like I've gotta wire one in from scratch. The Haynes manual I have makes no mention of a heated rear screen (apart from replacing the bulb in the siwtch in the supplement).

 

So I come looking to my expert friends on OSF. I guess the initial questions I have are:

 

1) Where should I get my live feed from? The II post on the ignition barrell is pretty choc-o-bloc.

 

2) I guess it needs a fuse, what rating?

 

3) The switch I have is from a facelift/Mk2 capri. Will this handle the load, or does it need a relay?

 

4) What gauge wire do I need to run to the screen?

 

5) Am I right in assuming that it earths by screwing in to the body work near the screen pillar?

 

Cheers,

Jim

[Spanner_monkey]

Iv never worked on a capri but for most rear screens I would personaly connect it as follows:

 

1) I would usualy take the ignition live from the key or from the fuse board.

 

2) 8amp should be ok

 

3) I would think it would need a relay

 

4) 2.5mm

 

5) Yes it should have a terminal to earth to the bodywork

 

 

Hope that helps

[jimbo]

Cheers for that Spanner Monkey

 

On that basis, and nicking the wiring diagram form my Mk2 escort Haynes

manual, I have come up with the following. Does this loook OK to you guys

 

 

In the diagram, the relay is rated 16A, does this mean the fuse should be 16A too?

 

Cheers,

Jim

[Vista]

Not if it needs 8 amp protection, fuse should always be the weakest point of a circuit.

 

Have you established what current the heated rear screen draws?

 

edit: and no, that drawing doesn't look right.

[jimbo]

Not if it needs 8 amp protection, fuse should always be the weakest point of a circuit.

 

Ah! yes good point The hangover is making me a bit slow this morning.

 

Have you established what current the heated rear screen draws?

 

How would I do that?

 

Re: the drawing being wrong.....I've just done some googling, and seen that I'm plugging in to all the wrong terminals on the relay (But I'm following the Haynes wiring diagram, honest*) ....Is that all that was wrong with the drawing Scott, or was there something else?

 

*Not the first time Haynes wiring diagrams have let me down!

[Vista]

Re: the drawing being wrong.....I've just done some googling, and seen that I'm plugging in to all the wrong terminals on the relay (But I'm following the Haynes wiring diagram, honest*) ....Is that all that was wrong with the drawing Scott, or was there something else?

 

*Not the first time Haynes wiring diagrams have let me down!

 

Your switch cct is wrong, if you trace it through you have it connected across two positives = no current flow.

 

Here's how I'd do it, the ones marked ign live should be live when the key is on position two (as illustrated in your original drawing)

 

[jimbo]

Cheers Vista!! That's really appreciated. It's a lot clearer now

 

The Haynes for Mk2 escort and the Mk2 Capri both suggest that the screen heater shares the fan heater fuse, so I might go from that one. That said I think I need to research which fuse does what first......

[Vista]

No worries, hope you get it sorted out