Rear wiper motor is stuck ON.

Rear wiper motor replaced along with the fuse in the fuse box with no impact (i.e. the wiper is still operating non-stop).

Vehicle electrician tested steering wheel wiper stalk but found no fault with that switch mechanism.

Working assumption is that the relay has fused ON causing the wiper motor to continuously operate.

I've hunted high & low for the location of the rear wiper relay for a 'new' ford focus to no avail, can anyone help locate the relay or tell me if there even is one on the new ford focus for the rear wiper operation.

Please note I am looking for the Relay Switch, NOT the fuse, which I know (71) and have replaced.

There are very few relays on modern cars, perhaps just on some high power circuits.

I would expect it's just controlled by the BCM. 

Right’O, appreciate the insight… any thoughts on a possible diagnosis as I’m pretty much stumped as to a cause of this sort of issue… short of a BCM fault/replacement?

6 minutes ago, Louis123 said:

Right’O, appreciate the insight… any thoughts on a possible diagnosis as I’m pretty much stumped as to a cause of this sort of issue… short of a BCM fault/replacement?

Why did the auto-electrician stop after the stalk?  He should've continued testing to pinpoint where the fault was.

It is possible that the BCM's faulty, but with only one fault and on a Mk4 Focus, seems unlikely.  I'd be more inclined to think it's a wire shorted out so it's bypassing the BCM switch altogether.  But will take some more multimeter testing to prove it.

It could also be a fault with the Motor.

It's a long time since I stripped one and if they are still the same as before then there is a permanent feed to the Park Circuit and it only stops because there is a cut out in the circuit at the Park position that breaks the circuit.

If you haven't done so before try disconnecting the Battery for half an hour to reset the BCM, might not work but will cost you nothing.

5 hours ago, Louis123 said:

Rear wiper motor is stuck ON.

Rear wiper motor replaced along with the fuse in the fuse box with no impact

Words fail me.

Wiper multifunction switches just send a LIN signal (for all Functions) to the front wiper motor/module. Front wiper module then sends an earth to the rear wiper relay. The rear wiper relay is inside the rear wiper motor. Unplug the front wiper motor, see if the rear stops then. It could be a problem with the front motor/module. That is the "brain" for all wiper and washer functions. If it carries on with the front disconnected, it could well be stuck relay contacts. According to the diagram I have, the rear wiper fuse is 73, not 71

These are the Focus Mk4 wiper schematics:

Disconnect wire/pin 11 (Orange & White) from Connector C1655 - under the bonnet very near the front wiper motor. That is the control wire for the rear wiper.

It is worth noting that the Fuse numbers in the Ford Wiring Diagrams are often different from the ones in the Owners Handbook.

I did not notice in my earlier post that the Motor had been replaced so ignore that comment, whoever did it must have been thinking along the same lines as me although I would have tested the old Motor first before fitting a new one. 

It looks like the rear wiper relay is built in to the rear motor assembly. So if that’s already been changed, it’s not a relay problem. 

21 minutes ago, alexp999 said:

It looks like the rear wiper relay is built in to the rear motor assembly. So if that’s already been changed, it’s not a relay problem. 

It could be a fault with the Canbus control module built inside of the front wiper motor. Details of it's operation are not fully shown in the schematic, but the controller sends the power to the rear wiper via connector C1655 on pin 11 (orange & white wire). I never had a problem like this on my Escort Mk2 🤣

23 minutes ago, unofix said:

It could be a fault with the Canbus control module built inside of the front wiper motor. Details of it's operation are not fully shown in the schematic, but the controller sends the power to the rear wiper via connector C1655 on pin 11 (orange & white wire). I never had a problem like this on my Escort Mk2 🤣

I think C1655 is pulling to ground. Power comes direct from the relay in the battery box (which also powers the fronts). 
 

It looks like the rear motor assembly relay defaults to park and the motor is only powered when “D” is grounded. I would be checking for continuity to ground on that cable as it may be shorting and no longer controlled by the LIN bus module in the front wiper assembly. 

13 hours ago, Tizer said:

It is worth noting that the Fuse numbers in the Ford Wiring Diagrams are often different from the ones in the Owners Handbook.

I did not notice in my earlier post that the Motor had been replaced so ignore that comment, whoever did it must have been thinking along the same lines as me although I would have tested the old Motor first before fitting a new one. 

Handbook fuse diagram labelled 71 which was how I isolated in the first instance so I know that to be the correct fuse.

Motor replaced myself (£2 to return once determined it wasn't the issue, cheaper than a multimeter!)

 

The fuse is irrelevant anyway. If the motor is stuck on it can’t be the fuse. 

2 minutes ago, alexp999 said:

The fuse is irrelevant anyway. If the motor is stuck on it can’t be the fuse. 

Agreed, more just making the point I'm aware of it's location, have had other forums whereby folks appeared not to appreciate the difference between relay & fuse... and repeatedly pointed out fuse locations as a fix...

Weighing up the time, frustration and expense of continuing with diagnostics Vs. living without a rear wiper...

I'm by no means electrically illiterate but aware of my lack of expertise and limits (and the need to acquire a multimeter of my own).

Main motivation would be when it comes to replace the car in a year or two's time...

There is normally a Cover Plate on these motors that allows access to the Electrical  parts, if so then it ay be a good idea to take it off and have a look for anything that does not look correct.