Nissan Primera P12 Heater blower fan wiring

Hi, ive recently bought a 2002 primera SVE and the heaters constantly keep running until the engine is switched off.I then disconnected the fan speed control module and the fan still keeps running.Now im thinking something wrong with the blower wiring and to my amazement, the previous owner had choped and changed the 2 pin plug that goes into the blower so that it recieves 12v when engine started.Now what i'd like to do is put it back to how it should be but need to know how.http://s953.photobucket.com/albums/ae14/samsang/2002%20Primera%20SVE%20P12/?action=view¤t=03032010004.jpgOn the 2 pin plug, the thick blue wire with black line is connected to ground, ive found the other end so thats ok.the thick blue wire with white line is connected to 2 thinner wires (Blue with white lines)Does anyone have a circuit diagran or even a picture of the wires under the glove that i can go on.Thank you.

I just repaired my fan controller using a 79p thermal fuse from Maplins (part number RA17T). This is a lot cheaper than £37 for the Nissan part.

The original fuse is 140 centigrade but the 152 centigrade replacement will be fine. The original part has the advantage of being an insulated component but the replacement fuse has a metal body so use some high temperature sleeving to insulate it. I used polyolefin heat shrink tubing (without shrinking it on for obvious reasons).

Access and removal of the fan controller is easy enough if you have a long shafted number 1 pozi and do not suffer from claustrophobia. Full instructions can be found -> <- here.

Start by removing the white plastic cover. It slips easily off the metal heatsink.



Before going any further check the two terminals (top left in the picture) of the thermal fuse to check it is blown. If you just tag a wire bridge across these the fan will work again but you don't really want to risk destroying your car for want of a little more work.



Using a solder sucker (gobbler) unsolder the three transistor terminals and the two thermal fuse terminals. These hold the circuit board in place so you can remove the board. The board is double sided but not PTH so a little judicious brute force and ignorance will soon have it apart. Unscrew the transistor to release the clip holding the fuse in position.



Not only is the original fuse insulated it is smaller with thinner leads. Use a 1.0mm drill to widen the holes in the circuit board wiggling the drill to make the holes more like 1.1mm. I removed the transistor entirely so that I could cleanly re-mount it with thermal goo. Bend the leads of the new fuse to match the board holes, sleeve it and replace it under the clip. I also applied a little heatsink goo the the fuse just to be safe.



Don't worry too much about neatness but do  worry about the temperature rating of the sleeving you use and bell it out when you have finished to make sure that you have no short from the fuse to the heatsink.  Replace the circuit board and re-solder the 5 connections. Use a proper temperature regulated soldering iron otherwise you risk overheating the new thermal fuse, which would be bad.

Bell it all out to check the new fuse works and there is no short from the fuse to the heatsink before replacing the assembly and enjoying not only the cool breeze, not only the saving of 36 quid but enjoying most of all the pleasure of having avoided yet another a trip to your Nissan dealer with some dumb ass P12 electrical problem

nice work and cheers for sharing

I forgot to say thanks to samsang for planting the seed of the idea.

If norbert would like to promote this to the how to section I would be honoured.

Used to be - now I only do hardware for fun.
I went over to the darkside some years back and became a software engineer.