The heater fan on my 92 vogue se only works on high speed,
I assumed it would be a resistor problem, so after dismantling dash, fascia etc to gain access to heater end plate, the resistor appears to be ok, how many relays are in the heater circuit and where are they located, my Haynes workshop manual is of little assistance in this area.
I am also chasing an ignition misfire problem, engine will run sweet whilst headlamps, ac, etc are switched off, but will misfire between 1800 and 3000 rpm when electrics are switched on,the vehicle has been fitted with new plugs, leads, distributor cap and rotor button (this seemed to almost fix misfire for some 4000 K but it is now back with a vengence), distributor air gap has been checked as have voltages at coil and ignition module.
An 85 amp Bosch alternator is fitted and batteries retain full charge.
I am just about out of ideas and "she that must be obeyed" has starting making derogatory remarks concerning the Rover's parentage.
The heater fan's problems lie with the contacts of the switch. Clean them up and add a little lubrication. This has cropped up before. Since you've already had the dash apart, taking the switch apart should be easy for you.
Check/clean/tighten the earth connections on the ignition module. This partic ular minor problem has manifested itself in many ways, but the bit about what happens when the voltage drops a bit (lights on) points to it.
Its pretty well known that a Bosch alternator transmits a lot of electrical interference into the wiring and this affects the ECU, through the interference entering the ignition wiring near the alternator.
The fix is to either reroute the wiring away from the alternator or to shield it with coax earthed at both ends.
A forumite in tassie had this problem a few months ago and recently PMd me to say this had fixed it.
I have 2 Bosch alternators but coax to a unichip and back and have had no probs.
Regards Philip A
Thanks Langy,
In my earlier correspondence I omitted to mention that I had started the heater job by removing, dismantling, cleaning, the switch contacts as well as substituting the A/C switch to no avail.
I have also removed the ignition module, mounting plate, cleaned and refitted using heat sink paste, alas no improvement to misfire.
Thanks also to Phillip,
When you mention co-ax is there some sort of sheathing I can use or am I looking at replacing the wires from the module to the coil, should I also be concerned about temp sender wire and coil to ECU wire ??
You would think I would be used to this sort of thing having owned Pommy vehicles for over thirty years but my patience is starting to wear a little thin !
You replace the wires with coax which you can get from Dick Smith or Jaycar.
To be really sure a reroute to the back of the engine and then along the LH Guard would maybe be even better.
AFAIK the only problem is the signal wire which runs over the alternator.
Regards Philip A
there is resistor unit located in the bowels of the decker panel that controls the fan speed. The wires from the fan switch go to this unit.
Thats the easy part. getting it in and out is the difficult bit. I have likened it to the female ********. However this one just happens to be hidden behind a chastity belt!
Fairly cheap to replace. These are a wire wound unit around a ceramic tube and the most common cause is weathering of the insulating coating on them causing either shorts or degradation of the copper. I vowed never to do one of these again and coated mine in heatproof engine epoxy (10 coats) for good!
You need small hands and lots of patience.
Dont pull at the wires as you will end up in the corner of your workshop sobbing in the foetal position!!
One or two Valiums have been known to be helpfull prior to attempting this!!
But i digress.........
Pdf of workshop manual page for resistor pack is included.
If i remember correctly there is a plug or something behind the dash that is very hard to get to. I tried to do mine thru the decker panel and had a myriad of pliers and clamps to hold things in place and stop them from falling back into the dash, plus a ginormously overflowing swear jar!
As for the alternator, Phillip is correct in the Bosch alternator interference. If you still have the original Marelli alt, get it rebuilt or look for a later D2 100A unit. As far as i know these will fit the Rangies but you need to change the pulley over as the D2 has serpentine drive.
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