Heater Blower Not Working

wilkobob · Post by **wilkobob** » 30 Aug 2005, 22:52

We have tested the old motor which is knackered (does not spin), so have bought another from a scrapper which we have tested and it spins without any problems, as soon as we connect it into the car into position it just clicks once and thats it.
We have tested that there is power at the two thick wires (red and black) which disappears when the ignition is turned off but were not sure about the smaller wires, there purpose and how to test them.
Any help would be appreciated, seriously becoming stressed. [V]
Car is a p-reg Xantia 1.9 TD, with air con and an "auto" setting.
Cheers,
Simon

Post by **Peter.N.** » 31 Aug 2005, 03:27

When you tested the new motor, was it connected to the old car? only they wont work witout the correct voltage on the thin grey? wire, thats the one that regulates the speed by biasing the transistors on the motor, it comes from your control panel. If you connect a resistor of about 100 ohms between the live feed (thick red wire) and the grey one, it should run, if not the motors regulator is faulty, if it does, your control panel is either faulty or has no supply.

wilkobob · Post by **wilkobob** » 31 Aug 2005, 05:53

I "hard wired" the motor to a car battery, and it spun up full speed. If its on the car, it works if you disconnect the pink wire (the thin one that branches off the earth) on full speed, and the controls have no effect. The old motor does nothing. When the pink wire is connected, the new motor does nothing. Any ideas, as im running out of them myself.
When you say control panel, do you mean the panel with the slider controls on it?
Ive tried using the resistor on the old motor (its the built in type, as its an air con model, with the auto setting) and its still exactly the same.
Help would be useful, as the second hand motor cost over £70, and its rather a waste if I cant get it to work.

Post by **Peter.N.** » 31 Aug 2005, 14:06

If when you hard wired it you had nothing connected to the pink wire it should not have run at all, (I thought it was grey but I am colour blind) as there would be no 'switch on voltage', if it ran flat out that would indicate that the transistors are short circuit, a very common fault. The only thing that I can't understand is that it should'nt behave in the same way in your car. Try checking for 12 volts on the motor when it is connected, it could be that you have a high resistance circuit due to a dodgy fuseholder or siimilar. Another thought has just struck me, have you tried it with the engine running? I've been caught like that!.

wilkobob · Post by **wilkobob** » 31 Aug 2005, 14:24

If its the transistors, why does it do exactly the same when connected to the old motors transistors?
When the motor is plugged in, theres 7.5 volts at the terminals (not 12). There is always about a 5 second delay (when you turn iginition on, or short the wires in the brown connector from the ignition, bypassing the ignition, but still turning the ignition on) before it spins up (only when pink wire disconnected).
The other thin wires dont carry a voltage for the first 5 seconds either, then theres anywhere between 3 and 7.5 volts down 1 of them (I think it was white). This is not connected to movements of the slider control, its completely random.
Im lost with it all, its just not as simple as id expect it to be, and I cant understand how the slider control communicates with the motor.
The only other thing I can think of that may be of use, is that the old motor is burned out.

mezuk04 · Post by **mezuk04** » 31 Aug 2005, 15:01

Rang CPC and tried to order both Transistor types which have been mentioned on a previous post, sadly there a none stockable item and therefore takes about 30 days for delivery so have put a hold on that to find any other places they are sold.
They would appear to be the manufacturers code
2N5880 16A
2N5884 25A
Does anyone want to buy my Xantia? [V]

mezuk04 · Post by **mezuk04** » 31 Aug 2005, 15:05

Ok so another thread suggests this company >
http://uk.farnell.com/jsp/endecaSearch/ ... ch#results
but which one is it im meant to order?

Post by **RichardW** » 31 Aug 2005, 15:36

Trouble is, the slider does not talk directly to the fan, it does so via the climate control ECU. I guess you should get a permanent live from the ignition switch, and then another wire will carry the switching voltage that tells the fan how fast to run. With the slider in positions to the right of the stop point, the speed of the fan should vary according to the slider position BUT if you have the direction on full demist, the ECU may override the fan setting. On mine it the fan sometimes appears to stop responding to the slider, and does its own thing, but most of the time it's OK (and I just leave it in auto).
Note that as mentioned above, the fan only comes on a few seconds after you start the engine (although it may time out on ignition switch on I suppose, but I've never tried that).
Just re-read your post. Take the red wire as live, and the black as earth. Possibly: the Pink wire is the sensor telling it the engine is running, voltage goes to zero when the engine is running (connected into the battery warning light perhaps?). The white wire is the switching wire. Sometimes the fan comes on high when initally swtiched on, depending on the car's internal temp - maybe this is why you are seeing random fluctuations?
So, I would try: fan in manual, air direction set to something other than demist, and engine running. See where that gets you (down the pub probably, looking for one of Marty's 'special' jackets...!!!)

Post by **Peter.N.** » 31 Aug 2005, 17:11

The transistors are part of the motor assembly, unless you have bypassed them and connected straight to the motor. The climate control vairies the voltage on the control lead according to the blower speed setting and the difference in temperature between the the air its blowing, and the interior of the car, if you connect a low value resistor between the red and pink leads, this should switch it on, assuming you have 12 volts across the blower terminals.
The transistors seem to be different every time I get them, if you have a data book, any TO3, NPN transistors rate at 15 amps or above should be OK.

Post by **Peter.N.** » 31 Aug 2005, 17:13

Sorry RichardW, I hadn't read your post properly!

Clogzz · Post by **Clogzz** » 31 Aug 2005, 18:41

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Peter.N.</i>

I thought it was grey but I am colour blind
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Don't say that Peter. [:)]
The forum members should know about your distinguished career in colour television.

Post by **Peter.N.** » 31 Aug 2005, 19:15

Oh yes!...I'm not completely colour blind, just the common sort, red/green..as if that didn't matter.

zzf00l · Post by **zzf00l** » 01 Sep 2005, 02:00

Re Resistor Source (dead easy to fit)
http://www.andyspares.com/discussionfor ... rms=blower

mezuk04 · Post by **mezuk04** » 01 Sep 2005, 23:22

Well Wilkobob came up with the brilliant idea of disconnecting the battery and guess what i have a blower motor that works, now just to get an air con compressor at the scrappie at the weekend and hopefully it fits and then off to get someone to sort it for me.