Heater Fan Is Intermitent

[Guest Buck_ejit]

I didnt want to Hijack the other thread as I am not sure if its the same problem..

 

My Fan comes on and off when ever it feels like it ... Sometimes it will come on 20 seconds after I have started the car other times it wont come on at all. I will get in after work and strangely it will be working again.... I would like to point out that my Rear windows demister always works as I have seen other posts about it stopping as well ... but mine works when the blower has stopped......

 

Any ideas would be good ... cos now the winter is hitting I need it for my 40 mile trip to work every day...

 

My car is a 1999 2.0 HDI LX

 

p.s This site helped me change the rear spheres on my car... she ride like a gennie's carpet now on the bumps

[skysurfer]

Just fixed mine. (2000 Xantia 2.0 HDI Exclusive).

It wouldn't run at any of the low/medium speed settings, only flat out and even that was only when it felt like it! If the windscreen was all misted up you could bet that was when it wouldn't run at all.

I replaced the 2 large transistors on the speed controller module (curved aluminium heatsink) which is mounted next to the blower motor which is above the passengers feet. Re-fitted the repaired module to the car last night and all is working fine.

The transistors I fitted were MJ11015 obtained from eBay for £6.51 delivered for the two. The existing transistors (type FW26025A1 on mine but they do fit other types I think) are fitted with rivets which need to be drilled out from the non PCB side and punched out and then the transistors need to be unsoldered, using solder braid or a solder pump. The new transistors are fitted using M4 screws/nuts in place of the rivets and they need thermal paste on the underside of the transistors. I also added a solder tag to each of the transistors then linked the tags with a wire and then also wired the tags to the body of the relay on the PCB as I didn't like to trust the corroded heatsink as an electrical connection. (This is perhaps overkill!)

If you're not into drilling/soldering then you will need to get a replacement speed controller module. (Often incorrectly called a resistor module. I think this was because on the early Xantias which didn't have the "Auto" fan speed setting this module was just a number of resistors). I think the module is about £40 on eBay.

 

Things to try first:

1. Check you have about 14V (engine running) between the thick red & black wires which go into the brown 4-way connector on the fan unit both when the fan runs and when it decides it isn't going to.

2. If you don't have the above voltage or don't have a meter to check it then (I hear) there is a green relay above the drivers accelerator pedal which you could try re-seating. (Pulling it out of it's socket and pushing it back in).

3. Check the 4-way connector on the fan unit is making good contact. On my old 1997 Xantia 1.9TD SX the red contact was intermittent and I used to re-seat the connector to get the blower to work. (The ignition may need to be cycled to get the fan to work after moving the connector). Eventually the brown 4-way connector plastic melted and I had to fit a new contact on the red wire!

4. Try oiling the fan motor bearings. If the windscreen has been replaced and the black plastic tray between the windscreen and bonet has not been glued back onto the new windscreen then you will get rain dripping into the fresh air inlet which fills up the housing that the blower fan motor is sitting in. In any case It's worth oiling the fan bearings if you take the motor out. I used "3 in one" oil aerosol with a long tube. (WD40 isn't much good as a long term lubricant). Try not to get too much on the motor brushes. If the motor has been really stiff to turn then it may also have blown the speed controller.

5. For those with a pre 1998 Xantia, it won't have the green relay and will be prone to the ignition switch contact going intermittent (if this is the cause then you will find that the rear window heater won't come on when the fan fails to opperate). I had this (along with another connector problem) on my 1997 1.9TD SX. If the ignition switch is the problem then it is best bypassed with an additional relay. This is a fairly simple job. I remember I did mine in a Sainsburys car park! The relay is fitted under the stearing column. A Google for "Xantia heater/blower fan relay" will probably get you the info for this. (Won't apply to Buck_ejit's 1999 vintage Xantia which I assume already has the relay fitted above the accelerator pedal).

 

When you've got it working, don't forget to fit the cable tie which holds the brown 4-way connector onto the underside of the fan housing. Otherwise the connector will work it's way out and this can also cause the connector to overheat and cause aditional damage in a few months time. (Been there!)

 

 

Interesting things I noticed in my recent investigation:

1. I believe that the 2 large transistors are responsible for providing the 3 (or so) medium speeds of the fan and the relay on the same module closes for the full speed setting. I was supprised to see that the full speed setting is also effected (works when it feels like it) when the transistors are blown. (For anyone inrerested - the "Emitter" pin was open circuit on both of the transistors that I removed).

2. While I was waiting for the transistors to arrive, I temoprarily fitted the fan motor and speed controller from my old Xantia 1997 1.9TD SX to my 2000 2.0 HDI Exclusive. For some reason the single wire connector (which needs to be connected to the blower assembly (in addition to the brown 4-way connector) was 10 cm too short and had a female connector which I couldn't connect to the 2000 wiring loom as that also had a female connector! When I tried the fan without this single connection the fan briefly runs to about 1/3 power for a couple of seconds and then goes back to a very slow idle. So if anyones fan behaves like that the they may have a break in that single wire connector. I made up an extension/adaptor lead to connect up the single lead and the 1997 vintage fan then worked fine on the 2000 Xantia. (The 1997 1.9TD SX also had aircon and a fan speed selector with the "Auto" setting position).

 

Good luck!

 

Alan

[Guest Buck_ejit]

Damn ......

 

That was one hell of a reply.....

 

But A crackin one at that. I am a total Noob at electrics, so almost all of it went way over my head, but I will print it out and find someone who will understand it all...lol...

 

Cheer Buddy I am sure that will be very helpfull to a LOT of people on here...

 

Buck aka Darren.....