The 75 and ZT Owners Club Forums - View Single Post

SimonP · 27th April 2021, 23:13

Good evening,
A search for schematics and other information led me to the club forum and this thread. What a wealth of information!
A massive thank you to those that have posted over the years!
I've read all the way through over the past few days, going over some information but still need to ask some questions.
I have two FBH, one is from a Rover 75 and the other from a Range Rover L322.
The Rover 75 unit did work but became more intermittent.
I swapped the ECU onto the L322 unit, symptoms were the same so pointing to an ECU issue. I was unable to communicate with it using WTT.
Only a couple of days ago I learned I was using the incorrect setting, should be "BMW".

With the Rover 75 unit I removed the massive blobs of silastic steadying the electrolytic capacitors and found the 4k75 resistor near the centre one open circuit, so replaced it. This seems to have fixed the fan fault.
The others near the Elmos bus IC tested ok.
Since removing the silastic I now seem to have a glow plug/flame monitor open fault.

I have seen post some pages back where someone had a schematic and parts list from Hella. I would very much like to get hold of this info to help me repair my FBH ECU.

The Range Rover unit obviously would not respond to +12V on pin 1 but does (now I know to use the BMW setting) allow me to connect via WTT and successfully run all component tests. Just not start the heater.
I removed the silastic on this unit too, the blobs were much smaller, about the size of a pea and there were no signs of corrosion.

Researching on the Range Rover unit, it would seem that it is possible to change the BMW units from analog switching to bus controlled and vice versa, BMW TIS explains which setting to choose versus production break if replacing a heater.
Problem is, I cannot get my scan tool (Topdon ArtiMini) to communicate with it. I've used a breakout box to interface with the heater.
Before investing in INPA, I would like to know if it is possible to communicate with FBH "off the car" with it.
Robinson Labs offer the service but I haven't had a response from them so am looking to change the function of the unit myself.

I would like to get at least one FBH up and running, if I can get the other one running too, it will do nicely in my workshop for next winter!

Thanks

Simon.

27th April 2021, 23:13	#315
SimonP Newbie None at the moment Join Date: Apr 2021 Location: Manchester Posts: 2 Thanks: 0 Thanked 0 Times in 0 Posts	Good evening, A search for schematics and other information led me to the club forum and this thread. What a wealth of information! A massive thank you to those that have posted over the years! I've read all the way through over the past few days, going over some information but still need to ask some questions. I have two FBH, one is from a Rover 75 and the other from a Range Rover L322. The Rover 75 unit did work but became more intermittent. I swapped the ECU onto the L322 unit, symptoms were the same so pointing to an ECU issue. I was unable to communicate with it using WTT. Only a couple of days ago I learned I was using the incorrect setting, should be "BMW". With the Rover 75 unit I removed the massive blobs of silastic steadying the electrolytic capacitors and found the 4k75 resistor near the centre one open circuit, so replaced it. This seems to have fixed the fan fault. The others near the Elmos bus IC tested ok. Since removing the silastic I now seem to have a glow plug/flame monitor open fault. I have seen post some pages back where someone had a schematic and parts list from Hella. I would very much like to get hold of this info to help me repair my FBH ECU. The Range Rover unit obviously would not respond to +12V on pin 1 but does (now I know to use the BMW setting) allow me to connect via WTT and successfully run all component tests. Just not start the heater. I removed the silastic on this unit too, the blobs were much smaller, about the size of a pea and there were no signs of corrosion. Researching on the Range Rover unit, it would seem that it is possible to change the BMW units from analog switching to bus controlled and vice versa, BMW TIS explains which setting to choose versus production break if replacing a heater. Problem is, I cannot get my scan tool (Topdon ArtiMini) to communicate with it. I've used a breakout box to interface with the heater. Before investing in INPA, I would like to know if it is possible to communicate with FBH "off the car" with it. Robinson Labs offer the service but I haven't had a response from them so am looking to change the function of the unit myself. I would like to get at least one FBH up and running, if I can get the other one running too, it will do nicely in my workshop for next winter! Thanks Simon.