Range Rover Light Washers and Alarm

A little while ago, an annoying glitch occurred on the RRC.  When arming and disarming the alarm/immobiliser, it all functioned correctly but the hazard lights no longer flashed (3 short flashes arming and one long flash disarming is normal).  The guys at Rogers of Bedford quickly advised that this was very common and the fault was a blown fuse in the interior fuse box beneath the dash.  After a lot of searching (the previous owner never did give me the Owner’s Hand Book as promised), I found the offending fuse.  Of course, it was the second last fuse in the box, pulling and checking all of them in turn, but for other RRC soft-dash and 300Tdi Discovery owners, look for the 20A (yellow) fuse second from the right of the upper satellite fuse box (apparently LR fitted some boxes the wrong way around, so it could in some cases be in the bottom left corner).  The symbol denoting the fuse on the legend is a picture of the hand book with a small head light and washer jet fountain adjacent.  There’s a clue in that statement…

Replacing the fuse rectified the problem instantly, but it was back a few days later.  A further replacement resulted in a third blown fuse after about a week.  So, what was causing the fuse to seemingly randomly blow if the hazard lights usually worked with the alarm, the hazard circuit worked normally off its dash switch and the circuit takes under 20A anyway?

You’ve guessed it – the fuse is shared with another circuit; that of the head light washer pump.  On the RRC soft dash, the bumper is fitted with two small plastic pedestals containing washer nozzles.  these are fed from the same bottle as the windscreen and tail gate washers, but have their own dedicated pump.  This pump is a damned sight bigger than the single pump that deals with the four windscreen nozzles and puts out very high flow and pressure – the bottle quickly runs down when the head light washers are used.  The head light washer pump is not controlled by the driver.  It’s an automatic function that is activated only on release of the windscreen washer stalk switch when the head lights are switched on.   That is why the fuse only blew intermittently – using the screen washers during the day had not triggered the pump and thus not blown the fuse, but driving home from work at night and cleaning the screen had done just that.  So the fault was in that circuit and had to be a bad pump motor or a short between the motor and its control relay.  The wiring looked good, so the pump was removed and stripped.

To get that pump out of the washer bottle, the electrics need to be disconnected from the top, the U-clamp released at one end with a stubby +head screw driver and the hose disconnected by loosening its Jubilee clip.  It’s all a bit fiddly in such a tight space.  Once the pump was out, I disassembled the casing into it’s four main components, none of which are bonded or welded – the lower casing, upper casing, upper casing’s terminal seal and the exterior sleeve that protects the main case.  Once the main halves were separated, the motor was removed.

The motor’s exterior steel case was covered in surface rust but the capacitor and resistor on the top looked fine, the stainless steel shaft was unblemished and I could see no problems through the cooling slots.  The shaft was seized solid, though.  I left the motor soaking in petrol for a few minutes before breaking the shaft free with a pair of pliers.  Spinning the shaft over buy finger tips after that seemed smooth, so I flushed it in petrol again to wash out any contaminants, then purged it with silicone oil spray before testing with jump wires from the vehicle’s battery.  It spun up fine, so I reassembled everything and the system now works properly.  I’m glad I was able to fix the pump, as they cost nearly £60 + VAT new and were specific to the RRC soft dash, according to my parts suppliers, so would be hard to source used.  If it had been irreparable, I would have simply left it disconnected until a cheaper replacement could be sourced or other priorities had been dealt with and the cost less of an issue, but hopefully this will allow anyone with a similar fault to fix it for free too.