Heater box

[ARCHP]

Dash now off I’m deep into heater box expecting to find resistor connections. Instead found this ( sorry if picture is upside down can’t sort that)

. It’s just a plate that screws onto the surface of the box. Have googled all the numbers on it but nothing. Am I missing something. There is a depression in the box to receive it.

[D366Y]

That looks like it has been fiddled with in the past to me
My original one looked like the left of this picture, a coil of wire surrounded by what I was is some kind of ceramic

If you have a multimeter you can test the resistor to see if it still works or is faulty, but it could be that the actual fan motor itself has seized and died so will need to pull out the big black heater box at the back and take it apart to have a look

[ARCHP]

There lies the problem there is no resistor. And there is no hole in the box case for the resistor to pass through.

. There is just an indent in the case for this assembly to sit in. Photo to follow. Also the back plate is quite thick, thicker than the pictures of yours.

[ARCHP]

This is the indent in the box

[ARCHP]

Looking at the back of the “resistor holder plate”, is that some form of resistive material between the two connectors that could provide the change in speed. I don’t know

[ARCHP]

This is the piece out of the car

[D366Y]

No idea what that is, looks like someone has tried to have a go at it before.

There is a helpful guide here: http://www.fordcaprilaser.co.uk/page151.html

And another here: http://www.fordcapriforum.com/forum/vie ... hp?t=49417

The resistor plate is held in the plastic casing that holds the fan, you need to split the box in half for the resistor to fit in the gap, will make more sense if you do it and hopefully you can see it in some of the pictures in those links - unfortunately I didn't take any pictures when I took mine apart

[nemo]

It could be some form of resistor, carbon rather than wire-wound, but it`s not standard, it`s been added by someone and looking at it it`s probs failed (they dissipate a LOT of heat - hence their mounting in the fan`s airflow) Easily checked if u have a multimeter, should be a couple of Ω (thanks Andrew )

[galuk1]

I agree it’ll be a resistor, either ceramic or maybe porcelain. The resistance part will be between the single pin and double pins, doesn’t look broken so likely to be inside the unit. If you have multimeter put it on ohms and measure, the standard is 2.5ohms. If you have that then it’s not broken, if you have infinite ohms then it’s knackered.

[Caprigear]

The one you have looks like one from a early MK1 heater box. I supply the new ones for the BEHR heater box used in the later MK2 and all MK3 heater boxes.

[ARCHP]

Thanks for all your replies. It’s the mounting that is baffling me. All the units that you talk about mount in rectangular hole created when the two halves of the heater box come together. This one sits on the surface of the box in a bespoke indentation, held on by one screw.

[ARCHP]

One other thing the heater box is a Smiths box part number 72 LG 18478 DA

[D366Y]

One other thing the heater box is a Smiths box part number 72 LG 18478 DA

In that case I'd say get in touch with Martin (Capri Gear) to see if he can help with a new box for you as a quick solution

[ARCHP]

Think I might stick with this one. It seams to work. With the negative connected to the dotted line the voltage across the bulb is just over 12 volts. With the negative connected on the solid line the voltage across the bulb drops to about 10 volts. That is whatever is in the component is dropping 2 volts. If connected to a motor this should see a reduction in speed. The other thing with just a bulb connected it did not get warm at all

[D366Y]

If it works it work, stick with it, may be that the fan has croaked it though so worth checking that