HRW relay

[Charless]

The manual tells me to look at C0044 for fitting my (Jan '96 export MPi) HRW relay:

However there is nothing but air and a fascia fitting there, the other two relays are there but no relay base for the one I want. Does anybody know if early ones had the base as a dealer-fit extra or fitted somewhere else?
Both the loom plug for the switch and the connector on the parcel shelf are fitted, but no base in the fuse panel!

[Mykel]

If the wiring is there, so should the relay socket. Could it be that it has dropped and is dangling around behind the fuse box?

[Charless]

No, I'm sure I looked everywhere!

That nut and bolt you can see below the red relay would foul a relay or base in the anticipated position! So maybe early ones had it elsewhere?

[Charless]

"Could it be that it has dropped and is dangling around behind the fuse box?"
Thanks O wise man from Schwalmtal - tucked up the back, only to be found by touch and now dangling around with a relay fitted! Some double sided sticky foam needed methinks!

[talkingcars]

Cable ties are my friend.

[Charless]

So I now have a secured relay in OEM base,
and a pukka non latching, non-illuminating OEM heated window switch that works:

But most importantly I have a heated front windscreen for those shitty months ahead when the raked F screen, parked outside overnight, takes 5 miles to become transparent when you have the top down! I drive 30 miles east to work and west in the evening - low sun and opaque screen=yuk!

and with the two sides of the screen elements connected in series it gobbles 18A from the poor old alternator! Once I know it can take it, I may connect them up in parallel and take double the current for faster results!!!

[Rob Bell]

Mine are in parallel Charles

Not been driving the car much recently, so sadly not much experience... yet!

[talkingcars]

I have one in parallel, have used it 3 times this week, not even a squeal from the alternator, not even at switch on.
I don't have the rear screen connected, maybe that's why.

[Charless]

Rob, James,
Do you plug yours straight into the HRW socket or use a second relay for switching?
To err on the safe side, I have rewired it so each side now has a 20A fused feed direct from the battery +ve and a common switched -ve through a 40A relay driven by the HRW socket. Now I just have to find the intermittent engine cutting out problem! :o)

[talkingcars]

I have taken a feed from the relay trigger wire from the HRW switch to a pair of 40A relays and used it to switch the relays.
Each of these relays have a 30A fuse on the top.
I have taken a power feed from the under bonnet fusebox.
Currently the rear screen is disconnected but I plan to fit a switch so that it disconnects the rear when the hood is down.

[Rob Bell]

I tried first using the HRW circuit directly. Unsurprisingly it blew the fuse. I decided not to muck about and fitted a 40A relay.

Because this is project Shed, and I have removed the EPAS ECU (steering column to come out soon for a non-EPAS version), I have used the EPAS power circuit to supply, using the existing 40A fuse. Works fine.

No squeal from the alternator, but you can certainly hear a change in engine note at idle when you switch the heated screen on or off!!!

[Rob Bell]

A bit more on how I fitted the wiring. I hadn't realised that I hadn't completed the text!

[Rob Bell]

Because there is no passenger airbag, I have mounted the heated front windscreen (HFW) relay in the passenger airbag slot in the dashboard - the blanking panel fits over the top, is not readily visible. I used a proper 40A relay base, so if for what ever reason the replay ever needs replacing, it can be easily accessed, pulled out and replaced.

I haven't got a picture of the 40A fuse - but it is the standard 40A fuse for the EPAS, so everything looks completely standard from a wiring perspective under the bonnet.

The main power connector looked like an industry standard item, so took a gamble on a 2x2 automotive electric plug (male/female) on the Bay of E's and struck lucky first time - my HFW plug clipped straight on - thus making removal very easy, and in the unlikely event of wanting to refit EPAS in its place very easy.

The earthing point is one of the standard harness earthing points on the passenger side A-pillar. Job done.

The relay mounting position and the way that you tap into the main power supply may not suit your application Charles, but hopefully this all makes some sense and provides an inspiration on how you might do it on your car?