ZX Heater - Only works in good weather!

PendulumZX · Post by **PendulumZX** » 13 Dec 2010, 22:50

Hello

My '95 Citroen ZX has been affected by the icy/cold weather this year, unfortunately whenever its left out in a freezing temperature, the blower refuses to work until the car warms up. It will not blow hot or cold during this time and operating the blower speed switch has no effect at all. But after the car has been driven for a few miles (and the car has warmed up) the blower will come on and work fine.

Its a big problem because the windscreen gets misty and I cannot clear it ... really dangerous. I have just ordered some RainX Anti-Fog to try and reduce this problem temporarily but I really want to fix the problem altogether if I can.

I thought it was maybe a relay or the switch itself getting iced up, so before I parked the car for the night, I made sure the switch was turned to Full blower setting, in the hope it would be "stuck" like that in the morning... but no, in the morning the blower still did not work at all for about half an hour until the car warmed up.

Any help greatly appreciated

citronut · Post by **citronut** » 14 Dec 2010, 07:57

hi and welcome

i cant think what the fault is but it is good practice to turn all high curent draw items of before turnning the ignition on or off, as this will burn out the ignition switch contacts prematurly,

which modle/engine is your car and does it have air con,

if its a non A/C the usual fan prob is the resistor pack which you will find under the skuttle between the bonnet and windscreen, and in the heater air intake duct below the domed mesh grill,

put your hand down the duct find the speed control unit, turn about a quareter of a turn pull out and unplug,

the only thing i cant see why it woulkd be this in your case

regards malcolm

Post by **Peter.N.** » 14 Dec 2010, 09:37

Just a thought, check your battery voltage after you have started the car, it should be around 14 volts, if its much lower due perhaps to a slipping alternator belt, some of the electronics won't work.

Peter

PendulumZX · Post by **PendulumZX** » 14 Dec 2010, 13:31

Thanks for the replies. I think I am wrong about the icy weather being the sole cause. It wasn't a particularly cold night last night, and I have just taken the car for a 30 minute drive and the heater did not come on. I popped back to my house to get my wallet to go to the shops, and when I returned to the car 2 minutes later and put the key in the ignition, the heater did come on.

Intrigued, I got the multimeter out and took some readings, as suggested by Peter, (which I cannot remember - I will repeat the whole exercise later and write down the figures), and when I turned the engine on to take the reading the blower went off!

It's obviously an intermittent kind of problem. This kind of intermittent electrical problem is nothing new to this car. For instance, I had a numberplate light which I had to bang before the MoT to get it to work (now fixed by bending the contacts for a better contact with the bulb), the central locking works when it wants to, dashboard lights have a mind of their own, the indicator sometimes goes crazy (common problem), the electric sunroof used to work intermittently but has failed completely now, the nearside headlight occasionally goes off which is fixed for a few months by twisting the cables leading to it... *sighs*!

I'll post back later with the voltage readings, many thanks.

Edit: Forgot to mention my car details as asked

, my car is a 1995 ZX 1.9 TD, without air con.

falling-out-with-my-car · Post by **falling-out-with-my-car** » 14 Dec 2010, 13:44

sounds a bit like the brushes are reaching the end of their serviceable life and sticking in damp weather.

PendulumZX · Post by **PendulumZX** » 14 Dec 2010, 22:47

After a few hours in the garage I think I am getting somewhere with this.

I now realise that the heater blower works fine when the key is put in and turned to the position where the glowplugs start heating. I have removed the blower and checked the voltage and it gets 12.13V during this time on settings 1, 2, 3 and 4. It will work indefinitely like this.

I didn't realise it worked on that key position before, as I usually get in the car, start the engine, and only then I try to turn the heater on (to find that I cannot). What I said about the icy weather being the cause, I think that was a red herring. Its just my bad luck that this would happen in icy weather.

After starting the engine, the heater blower gets no voltage. So I can rule out the blower being the fault. I have seen it spinning at all 4 speeds and it seems to work fine when its actually getting voltage.

Now this is the interesting part: when I go to turn the key to activate the starter motor, the blower loses power (as it's supposed to, I think, so the battery can deliver the most power to the starter motor), but then it never regains the power. I hence thought it could be a fault related to the ignition. I experimented with the turning of the key and have found that if I return the key from the starter motor position to normal position very slowly, I hear an extra click and the heater will come back on again. Its a bit hit and miss but I can get it to work half of the time.

I don't know where to go from here. I assume this is a problem with a switch in the ignition or something. I have never worked with an ignition before. Any tips on where to go from here?

Many thanks

Post by **Peter.N.** » 14 Dec 2010, 23:24

Sounds as though it could be a faulty ignition switch, I know they give trouble on the Xantia. The XM obviously has a different arrangement as the blower will only work when the engine running.

Peter

Post by **RichardW** » 15 Dec 2010, 07:51

Yep, sounds like the normal trouble with burnt out contacts in the ingition swtich. The solution is to identify the faulty circuit on the switch, then bridge it out with a relay - wires will be accessible under the column shrouds. There might be enough left in the swtich to activate the relay, but otherwise you'll need to take a swtiching feed from somewhere ignition swtiched, eg the cigarette lighter.

Peter - the blower on Mk2 (and maybe all A/C cars) Xantias only works with the engine running, but this is a separate low power feed - the main current for the blower (and HRW

) is still handled by the ignition switch - although Cit fitted a relay on Mk2 cars to take the load off the switch. XM is probably the same underneath....

citronut · Post by **citronut** » 15 Dec 2010, 08:07

my MK1 XANT blower usualy when working kicks in a few second after the engine is running,

what actualy causes the delay, i do here a click(relay??) just at the point the fan cuts in,

in the case of this thread it is a ZX so are they diferent,

i had a customers MK1 BX that used to fail the MOT on indicators not working,

also the electric widows did not function,

this was down to the ignition switch needing to be turned back a touch after it had sprung back from the starter position,

regards malcolm

Post by **Peter.N.** » 15 Dec 2010, 11:02

OK Richard, not to familier with Xantia's. I think there must be a voltage sensing circuit in the control system that doesn't allow the fan to come on untill the battery is charging.

Peter

PendulumZX · Post by **PendulumZX** » 15 Dec 2010, 17:45

Thanks. I have been reading all about the ignition mod. To be honest it sounds very very hard. I am not so good with electrics. Tomorrow I may take the cover off of the ignition to have a look and see if things are any clearer for me, but at the moment I feel like messing with the wiring could be above my skill level. I can use a multimeter and wire a plug, that is about it!

falling-out-with-my-car · Post by **falling-out-with-my-car** » 16 Dec 2010, 11:33

try hooking your battery up to a charger for the night and see if it makes any differance, although not the same car my xantia seems to prioritise and sometime the rear windscreen wiper or fan will not operate unless the battery is in optimum condition, charging it seems to put everything back in good working order.

it could be as above your electrical system is halting the fan until there is enough charge to run it.

how many people charge their batteries before or during a very cold spell of weather ie winter. short journeys in the winter with your lights on will also bring the charge level down. I wish my son would learn about this one he makes lots of short trips early in the mornnings and wonders why his battery goes flat even though his alternator is charging.

he wont accept that it takes at least 20 mins to put back the charge into the battery drained during starting the engine on his vauxhall.
if his journey is only 15 mins with his lights on full beam the battery will suffer eventually and not keep enough charge, esspecially in freezing temperatures, I'd check the fluid levels on the battery if it is not a sealed unit top it up with distilled water and give it a good over night charge and see what transpires from that first.

if it doesnt work after that then you can go chasing modifications until your hearts content.

Also if you have a simplex lock the internal pins are made of brass I fill the lock with lithium grease about twice a year by pushing the grease into the keyhole and inserting the key several times to work the grease weel inside to the brass pins this type if ignition lock seems to require maintenance quite a lot or as many people use steel keys the pins wear and finaly collapse because the lock drys out completly.
I have had a few of these ignition locks fail on Bx's until I started greasing them.

if the key sems a little tight going into the ignition give it a good feed of lithium grease one to make it last longer and two to see if it frees up the mechanism inside which might help in activating the fan if it has more fredom to move the internal componants.

Post by **RichardW** » 16 Dec 2010, 12:11

ZX is not that clever that FOWMC - ignition on, blower comes on. Possibly I guess if the charge is well down, then there might not be enough current to run the fan. Relay required to take the load off the dodgy ignition switch is my guess!

falling-out-with-my-car · Post by **falling-out-with-my-car** » 16 Dec 2010, 13:28

so it may be a low battery then?
might be worth a charge then before deciding to strip the ignition switch?

on another note I have a relay to protect my battery on an external 12 volt dc fuel pump I fitted to my xantia as a fuel system Mod for running on veg if the battery charge is down the relay will not function properly esspecially in freezing temperatures, it could be as simple as that a relay is not getting the correct voltage to activate.