Electronic Repair -- Heater control unit

Anybody know of and preferably recommend a shop to repair the unit?

Thanks Rider

Hopefully Heckler is still around

I tested all diodes , all working

In the two non working units I have the TR1 resistors are gone

TR1 Transistors are A965 Y3h , TR2 A2235 Y3f

I can use A2235 Y3f from the other none working unit , I am not too up on Resistors , Is it possible to use A2235 Y3f to replace A965 Y3h

I can only find A965 Y122 , as opposed Y3h, not too sure if it is an issue

Hopefully Heckler is still around

He emigrated with the job last year, air force I think? Anyway said his goodbye last year.

He emigrated with the job last year, air force I think? Anyway said his goodbye last year.

Sent him a PM , if these are common problems ; Stu Hagen in the states said he never came across a resistor going

I have 2 units here both not working , the two of them have the same resistors gone

TR1 Transistor A965 Y3h (PNP)

R10 Transistor (10k ohm (10K)5% 0.25W Resistor (Brown, Black, Orange, Gold)

Get pictures of the boards, resistors and their types. My dad will know what to replace them with. Hes a electroincs engineer and did my led conversion and fixed my burnt out board

Get pictures of the boards, resistors and their types. My dad will know what to replace them with. Hes a electroincs engineer and did my led conversion and fixed my burnt out board

Thanks , The schematic says R10 is a 1K resistor but based on its colour bands its 10K

I got these

http://www.ebay.ie/itm/10k-ohm-10K-5-0-25W-Resistor-Brown-Black-Orange-Gold-x10-x100-x500-x1000/111945227709?var=410892204491&hash=item1a10749dbd:m:m4PXkDi43hniQBV1n-3TA0g

https://www.ebay.ie/itm/191913738700?_trksid=p2045573.m570.l6004&_trkparms=gh1g%3DI191913738700.N41.S1.R1.TR6

Ok ill ask him when hes over

Thanks!

I tried to find a diagram for the control panel and could only track one down for the MkIII from a service manual. Did you have one for the Mkiv controller?

I recon the transistor is a PNP Toshiba product. Equivalent code 2SC2235 which comes in about £1.50 a unit or lots for £10.

Along with a 10 ohm resistor could be a cheap fix and you can become the new Heckler for air control panel fixes, you'd just need to add in LED upgrades.

Hey, my dad looked at the stuff you posted and the items you purchased and said they look fine. He did say that 10k ohms should have not blown though. How you did you confirm the transistors are gone?

He emigrated with the job last year, air force I think? Anyway said his goodbye last year.

I never Emigrated! I just changed Jobs! - Still in UK, still active on this forum

Heckler , what are your taughts on the schematic says R10 is a 1K resistor but based on its colour bands its 10K

One of the lads on the Irish car forum is sitting beside 2 Ex-Raf Electronic engineers , who was helping me with some Q's

Hey, my dad looked at the stuff you posted and the items you purchased and said they look fine. He did say that 10k ohms should have not blown though. How you did you confirm the transistors are gone?

Transistor was ok , just the resisitor in R10 was gone , used a multimeter and the Diode function , all other components looked good via the multimeter

- - - Updated - - -

Resistors I bought all are gone , so decided to use one unit for parts to make one good unit

Done so far

• Loom in the car has 12v to both pins
  
• R10 in both units was gone , 10K resistor
  
• I replaced both units with a working resistor
  
• Tested all transistors, Diodes & Resistors on the circuit board (all working)
  
• Solder looks all good on both units
  

Testing

Tried both units in the car tonight , (both where dead)

• the backlights on the units are working now
  
• None of the functions work
  
• LEDs to illustrate what function is selected is also not working
  
• Tested all transistors, Diodes & Resistors on the circuit board again (all working)
  
• Loom in the car has 12v to both pins
  
• Joggled the loom , nothing changed
  
• I also checked all fuses I could find associated with fans... in the kick panel -- all good
  

Background, It was a very slow fail over 12 months , what did fail was the ability to control the heat within the car , then over a few months some LEDs started to fail but flickered on/off intermittently , then the whole unit failed

Any idea's ?

Sounds like a bigger ball ache than its worth. Id just buy a working unit mate

Sounds like a bigger ball ache than its worth. Id just buy a working unit mate

Trying to find one is the problem, Ebay units are stupid money

Keron has none

would you mind asking your dad , what he would do next?

I am trying to get a loan of a working unit off my mate to rule out anything else

Trying to find one is the problem, Ebay units are stupid money

Checked recent Japanese parts auctions and the last one I found that sold, in December, went for Y5,000. That's about £32 so may be worth looking over there.

Checked recent Japanese parts auctions and the last one I found that sold, in December, went for Y5,000. That's about £32 so may be worth looking over there.

Keeping an eye out!

- - - Updated - - -

Checked recent Japanese parts auctions and the last one I found that sold, in December, went for Y5,000. That's about £32 so may be worth looking over there.

Keeping an eye out!

For other members

Some Tests you can do

To check the transitor, turn the transistor upside down, with the leads facing you and the flat face towards you, the left terminal is the base, the centre terminal is the collector and the right hand terminal is the emitter. Set your meter to the Diode test function, connect the black lead of your meter to the Base terminal and then connect the Red Lead of your meter to the collector and emitter terminals in turn and you should get a diode test indication for both junctions from the Base. Also connect the meter test leads between the Collector and Emitter terminals, there should not be any readings between these two terminals.

To test the Car loom and Chassis Ground

Test: 1 probe to the ground pin socket on the car loom (the one pin 9 connects to) and the other to the outer ring of the cigarette lighter. (IGN off and with IGN On), set the Multimeter to Ohms

Outcome: 5-9 Ohms measured, I tested both the Ill GND & HVAC GND, GND is good

Test: Capless sidelight bulb, ILL 12V & ILL GND ; HVAC 12V & HVAC GND, IGN On , DRL's on

Outcome: Both ILL and HVAC 12 V illustrated the same intensity of light, no issues with the 12v Plug

Test: Verify 12V HVAC / ILL is going to the circuit board, via 12V pins/GND's, IGN On , DRL's on

Outcome: Verified 12V with multimeter

Test: Check Fuses

Outcome: Verified HTR 7.5 amp Fuse is intact / CIG 15 amp is intact

Electrical Diagrams

https://1drv.ms/b/s!Ao-FTTt3GMhrh-hNdWWBCqLAbW-pvA

P246-254

H 12 Heater Control SW

H 13 Heater Control SW

Looks like we have a 50 amp heater fuse (Blower Motor control relay) in the engine bay fuse box, will take a look at it too ,

Interior 7.5amp fuse controls

Next Steps

Test for voltage at the button led's . Black lead on a good earth , red probe either side of the led

The a/c amplifier has power feeds on the ecu-b, cigarette lighter and the gauge fuse but bar the cigarette lighter if the other ones failed it would cause you greater problems and I checked the cigarette fuse earlier.

the a/c amplifier is earthed through pin 9 and pin 13 of the amplifier shown on page 243(check them on ohms to earth)

Check pin 14 to earth it's the the A/c dual pressure switch it should be low ohms if it's healthy

Got a working unit , all lights up but no functions work

It points to the AC Amplifier?

Its little consolation but you are not the only one to experience a non functioning unit. There is a thread on here from 2006 reporting a similar problem. No solution offered unfortunately but you could send a speculative email to the OP to see if they still have the same email address and did manage to resolve the problem you are encountering. You won't be able to PM them as the OP is a former member, from Ireland, but there is an email option on their profile which presumably still directs to their registered address. Or maybe you or some people you know, know who they are?

Its little consolation but you are not the only one to experience a non functioning unit. There is a thread on here from 2006 reporting a similar problem. No solution offered unfortunately but you could send a speculative email to the OP to see if they still have the same email address and did manage to resolve the problem you are encountering. You won't be able to PM them as the OP is a former member, from Ireland, but there is an email option on their profile which presumably still directs to their registered address. Or maybe you or some people you know, know who they are?

Thanks!

Its starting to get ridiculous