Welcome to our resource for MG Car Information.



MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG ZR ZS ZT Technical - ZS - strange heater?

Has anyone found that the heater on the ZS series behaves in a strange manner?

Central cool air/hot air switch doesn't make a great deal of difference - unable to get heated air unless LH rotary control is NOT set to windscreen.

On my previous car (414) the above control works as expected, ie you get heated air when control is in down position, fresh (cold) air when in upper position regardless of LH rotary heater selection.

Had this checked by dealer and all other MG ZS's behave in this "strange" manner.
Wonder if MGR have changed functionality?


HI Brett
Sounds just like my fathers Rover 400.

I get plenty of warm air, at the moment its set on screen all the time, I find it warms the whole car and no need to keep fiddling with controls!


Havn't really noticed, just assumed that it would work like it did on my Rover 416 but I will certainly have a good look.


Had the chance to have a good play with the heater controls on the way home from work tonight (I was not on the road at the time) and can confirm Brett's findings.

Upon checking the handbook it does state that 'Air will flow from the centre vents when face level, or foot and face level distribution is selected' (page 36)

Hope that this helps.



My ZS 180 has this problem. My dealer and I have investigated and found that the cable from the centr vent switch to the heater unit itself is fastened in the wrong position. This allow cold air out of the vents (and on to your left hand) no matter what you do with the heater controls. It is also the same on all Rover 45's.

My dealer has fillied in a "Product report form" to return to the factory to allow them to "investigate" this production problem and issue a TIB (Technical Information Bulletin) to get everyone's cars fixed.

Hope this helps

Trophy Blue ZS180 5dr

Many thanks for the investigations. The inability to have hot air on the windscreen without cold air on your face is annoying especially as the weather gets colder.

I'll print out this thread and mail it to my dealer.

cheers all
Brett Laniosh


I have the same problem, I noticed one morning before leaving for work and having to wait for over 20 minutes for the windscreen to clear. I took it in to a local dealer who said it was a cable that had come loose and all was ok now "guess what" emm not quite it does clear a little better but it still takes a good 10 minutes. Not sure what to do, now I have seen these comments I think another visit with these mails may help clear my problem and the screen a little quicker.


Eddie Wilmott

This has been an ongoing problem for ages....

Other heater control cables also seem to be 'forgotten' to be connected up at production.

My ZS120 showed exactly the same symptoms - air vent cable was found to be disconnected, cold air to face at all times.

Connect it back up and all was well forever more.

Not good during the cold weather though!

How much difference do you notice between the up (fresh air) and down (warmed air) positions Dave.
Since mine has come back, there is a VERY slight difference but so small it has to be measured using a digital thermometer!
Brett Laniosh

Brett - I'm not in my ZS at the moment - back Monday PM I expect. For the moment I am enjoying a ZR160!
I will check it out and report back.




I have the same problem, the change in air flow has not changed that much, the vent to clear the screen is a least half the power of any other vent, not sure what to do at this stage but as I said maybe I will take a print of these messages to my dealer and ask them to look a little deeper. How frustrating this morning, the car was covered in ice and I had to leave it running with the heater on full for 10 minutes and stand inside watching through the window to make sure my car was not nicked. (10 Minutes).

Can you advise who I should be speaking to at my dealer, I feel they are not aware of these problems with the heating system and want them to sort it.

Cheers A very cold Eddie.
Eddie Wilmott

Can someone clarify for me the correct operation of the central vent(s)? My ZS180 does produce hot air through the central vent (when it has warmed up) but ONLY when the air selection switch is set to the upper vents, otherwise it's cold air. I have a choice of upward facing or forward facing central vents but I can shut both off entirely.

Am I supposed to get hot air through this vent when the other side vents are warm? I ask because I tend to set the hot air onto the windscreen when I start up in these cold mornings, but get cold air sent at me through a central vent as a consequence. If I can't shut both the central vents off entirely I would at least like warm air coming through them!

My demister didn't work at all when I first got My ZS, took it back and they fixed it (didn't say how and when I asked was told that the person who had fixed it was not around). Anyway to cut a long story short, it stopped working again yesterday. My guess is there is something wrong with the cable attachment. Going to a different dealer next week for them to take a look.

The problem you descibe is EXACTLY the same as that which affecting me. It looks like a design fault - though interestingly no present on my P reg Rover 414!

Maybe as MG owners we are SUPPOSED to be used to bags of fresh air on our faces. This is RMG's way of making our cars have the classis MG feel!


This thread was discussed between 05/12/2001 and 03/01/2002

MG ZR ZS ZT Technical index

This thread is from the archive. The Live MG ZR ZS ZT Technical BBS is active now.