Heater blower inside car not working

Mickyboy · 15th December 2015, 20:11

Hi everyone,
I've been working on my father-in-law's car it is an MGZT CDTI, however the automatic temperature control seems faulty.

the heater blower inside the car will not operate at any speed, the ATC illuminated correctly, I have removed the unit and checked the two rear plugs, checked all ATC related fuses and swapped the under bonnet relays ( heated rear screen for the fan) but to no avail, the ATC unit has also been swapped for a known good working one.

I'm starting to run out of ideas I'm wondering if I disconnect the BCU and reconnect it would it lose its coding? As I imagine the BCU sends the earth signal to the relay.
Any ideas would be welcome
Thanks in advance
Mick

SD1too · 16th December 2015, 16:40

Micky,

My suggestion would be that you by-pass the electronic blower speed control module. It's on the side of the HVAC unit in the passenger footwell. One member had a faulty one of these, and another had a failed blower motor. There's been a thread fairly recently about this so I recommend a search; all the detail you need is there.

Simon

Mickyboy · 16th December 2015, 19:05

Quote:

Originally Posted by SD1too

Micky,

My suggestion would be that you by-pass the electronic blower speed control module. It's on the side of the HVAC unit in the passenger footwell. One member had a faulty one of these, and another had a failed blower motor. There's been a thread fairly recently about this so I recommend a search; all the detail you need is there.

Simon

Hi Simon I've just like to say thanks mate,

I've changed the transistor speed pack and that has fixed it, I also noted that with a volt meter if you connect the brown and the black it sends the fan motor into high-speed this could potentially save somebody the hassle in cold weather having to replace the transistor pack as a short term measure.
Kind regards Mick

15th December 2015, 20:11	#1
Mickyboy SERVICING AND DEALER DIAGNOSTICS MG ZT CDTI 135 + & MGZT CDTI AUTO 160 & ROVER 75 TOURER CDTI 160 TROPHY YELLOW Join Date: Aug 2013 Location: Hernebay Posts: 4,331 Thanks: 818 Thanked 2,414 Times in 1,141 Posts	Heater blower inside car not working Hi everyone, I've been working on my father-in-law's car it is an MGZT CDTI, however the automatic temperature control seems faulty. the heater blower inside the car will not operate at any speed, the ATC illuminated correctly, I have removed the unit and checked the two rear plugs, checked all ATC related fuses and swapped the under bonnet relays ( heated rear screen for the fan) but to no avail, the ATC unit has also been swapped for a known good working one. I'm starting to run out of ideas I'm wondering if I disconnect the BCU and reconnect it would it lose its coding? As I imagine the BCU sends the earth signal to the relay. Any ideas would be welcome Thanks in advance Mick __________________ [SIGPIC][/SIGPIC] T4 Owner Jobs done : new UBP, Spy hole mod, Rear hub(wheel bearing),plenum cleaned and emptied, Inline thermostat fitted,Full service, In car Digital tv/DVD Bluetooth Satnav etc, Replaced UBP, Restored headlights,Fixed airbag connection.replaced HP pump,replaced rear light seals,changed intercooler O rings. Jobs to do: ,replace drivers lock,.[/SIZE]

16th December 2015, 16:40	#2
SD1too Doesn't do things by halves Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007 Location: Former Middlesex Posts: 20,380 Thanks: 1,587 Thanked 3,749 Times in 3,181 Posts	Micky, My suggestion would be that you by-pass the electronic blower speed control module. It's on the side of the HVAC unit in the passenger footwell. One member had a faulty one of these, and another had a failed blower motor. There's been a thread fairly recently about this so I recommend a search; all the detail you need is there. Simon __________________ "Whatever is rightly done, however humble, is noble." Sir Henry Royce.