Xantia blower full speed issues after cold morning start 1.9TD

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Moiye
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My Cars: Xantia 1.9TD 1996 wagon

Xantia blower full speed issues after cold morning start 1.9TD

Post by Moiye »

I own a xantia 1.9TD 1996 break X1

I started my car this morning, start of the cold snow weather and the heater blower motor is running flat out in my car when I turn the ignition on to start it and read it's normally the transistors that's burnt out

I checked using this guide from this link
http://www.frenchcarforum.co.uk/forum/v ... =26179#top
"
Using a multimeter on the 2K range (or preferably on the diode test range) measure between the terminal marked "Output" (actually the motor negative return) in the picture and the heatsink. If you hare using a meter with a diode test range you will see continuity (600ohms roughly) one way and an open circuit if you reverse the meter leads. If you see a short-circuit or a very low resistance whatever way the leads are placed, at least one of the transistors are short-circuit (both are in parallel).

The transistors can be further tested with a meter on the diode test range by placing the negative test lead on the Base ("B") of the transistor and the positive lead to the Emitter ("E") and Collector (Heatsink) in turn. Both ways you should see continuity in the region of 900 ohms. Reverse the lead polarity (i.e. Positive test lead on the Base) and you should read an open circuit between Base and Emitter and Base and Collector. Short Circuits or very low resistances anywhere indicate faulty transistors.

If that checks out OK, a fault in the A/C ECU may be present. This is very rare however and it is more likely to be a wiring issue between the ECU and blower speed regulator.
"


I was getting 750 (expected 900) on the second test and very small readings on the first one (0.01) but I reckon one of the transistors never worked and was faulty as the Middle range fan speed didn't change anything until the second last speed setting and max speed prior to his issue occurring. so is it possible the blower wouldn't have this issue of being full speed if only one transistor was out or would both have to be gone for this issue to occur.

Also I took out the control panel for the fans speed lever and it has a sliding spring clip that slides along a circuit board changing the different speeds or so it should ... The springs are touching the circuit board from what I can see

I checked the voltage whilst adjusting the fan speed with the blower disconnected on the white wire with black wire, and thin brown wire with black wire. These wires from the blower wiring harness. No change in voltage and was at 0.01-0.02Volts for the thin wires. Does the blower have to be connected for this test to be useful or should it still give a reading from the fan speed control lever?

Thoughts ?
Fan speed lever issue
Transistors issue?
Any further tests and steps

I'm selling the car in 3 weeks so I'd like to fix it or I'll just unplug the fuze for the blower to stop it running non stop.

Any help appreciated
Cheers
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Old-Guy
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Re: Xantia blower full speed issues after cold morning start 1.9TD

Post by Old-Guy »

That thread refers to the Air con (Climate Control) blower control. There is a thread, with comprehensive instructions by CitroJim for repairing 'ordinary' heater blower speed-control modules. I had this problem several years ago, an easy fix if you're any good with a soldering iron.
2011 Grand C4 Picasso VTR+ 1.6HDi in Kyanos Blue
1995 Xantia Estate SX 1.9TD in Vert Vega "The Green Lady" - after 11 years now owned by XanTom
1998 Xantia 2.1 VXD Estate in Mauritius Blue - R.I.P. (terminal tin-worm)
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Re: Xantia blower full speed issues after cold morning start 1.9TD

Post by demag »

Yes not quite the same but I have done a solder repair on a Nissan and it worked perfectly after. It's usually a printed circuit burnt through.

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