Webasto Thermo Top V - Telestart T91 in TD5 Defender

[MBE_NZ]

Hi team sorry if this has been absolutely flogged elsewhere, I've trawled the forums and am still stuck...

I have a Webasto Thermo Top V heater retrofitted in a TD5 Defender (came from a VW I believe)

The entire electrical circuitry is independant from the vehicle (except connection to the battery) and it runs just fine using 1533 timer using W-Bus.

I recently aquired Telestart T91 and I have followed the remote "learn" instructions. I have connected the T91 to the heater both on it's own and with the timer connected but I can not get it to operate the heater.

When both are connected and the "on" button is depressed on the remote, the timer display shows "Tele - on" for ~13 flashes, then goes blank and doesn't fire.

if I hit the "On" button - then the "off" button it clears the timer screen instantly, so the remote appears to be being picked up

but I am unable to set the "mode" via the remote (only showing Green LED on remote for venting, I want Red for heating)

The heater still operates perfectly fine using the 1533 timer and instant flame, but I would like to get Telestart working too

Can anyone please advise do I need to purchase a "Y-Cable" or is there something I'm missing?

current wiring (also attached wiring diagram):
1533:
port 1 - OUT analog +ve = not connected
port 2 - OUT W-Bus to pin 2 on heater (and pin 2 on T91)
port 3 - +ve via 5 amp fuze (and pin 1 on T91)
port 4 - -ve / earth

T91:
port 1 - +ve via 5 amp fuze (and pin 3 on 1533)
port 2 - OUT W-Bus to pin 2 on heater (and pin 2 on 1533)
port 3 - OUT analog +ve = not connected
port 4 - Y Cable = not connected
port 5 - summer / winter - not connected
port 6 - -ve / earth

ALSO - The Webasto diagnostics software I have covers the heater and Telestart T100 - not the T91 and errors out when attempting to diagnose / program - so if anyone has a link to the diag tool for T91 I'd appreciate it too

[Maverik]

Are you completely sure the telistart is working as it should? i.e have you directly contected to telistart and unplugged the timer?

I run a T90 straight without a timer, so can't help you much, but will keep my eye out see if I can dig anything up.

Mav

[TSD]

It may be due to the configuration of your Thermotop and/or the T91. These things are more complex than any sane person would beleive.

Not all TT-V are the same, they may be configured (at build) to operate as a supplemental heater, or as a parking heater, or both, or possibly some other options.

Depending on configuration, it may refuse to act on commands to operate in other modes.

I have a TT-V in a Discovery 3, and a brand new T91 from a Skoda, plus a spare LR branded remote.

The T91 sends a general 'Heat ON' command. The TT-V rejects the command and replies accordingly.

T91 retries a few times, then gives up.

The 1533 Timer module, sends a different command 'Park Heat ON' which works fine.

Just to add confusion the two remotes have different LED indicator modes, despite sending the same commands via the receiver. The remotes seem to be programmed to act differently.

I have a small pcb that sits between the T91 and the heater, and translates the messages. It's working, but not yet at a stage that I'd let anyone else play with it.

Nothing original, several people have done this before.

There are other options for remote, from GSM remotes from BAS or Denhag, to using a cheap ebay remote control to activate the manual heating button on the 1533 timer.

[Maverik]

It may be due to the configuration of your Thermotop and/or the T91. These things are more complex than any sane person would beleive.

Not all TT-V are the same, they may be configured (at build) to operate as a supplemental heater, or as a parking heater, or both, or possibly some other options.

Depending on configuration, it may refuse to act on commands to operate in other modes.

I have a TT-V in a Discovery 3, and a brand new T91 from a Skoda, plus a spare LR branded remote.

The T91 sends a general 'Heat ON' command. The TT-V rejects the command and replies accordingly.

T91 retries a few times, then gives up.

The 1533 Timer module, sends a different command 'Park Heat ON' which works fine.

Just to add confusion the two remotes have different LED indicator modes, despite sending the same commands via the receiver. The remotes seem to be programmed to act differently.

I have a small pcb that sits between the T91 and the heater, and translates the messages. It's working, but not yet at a stage that I'd let anyone else play with it.

Nothing original, several people have done this before.

There are other options for remote, from GSM remotes from BAS or Denhag, to using a cheap ebay remote control to activate the manual heating button on the 1533 timer.

Now that's a comprehensive answer...

[MBE_NZ]

thanks for the feedback guys. I'm pretty sure that the wiring is OK - unless the Telestart needs to have the "Out analog" connected.

hadn't thought about the different commands being issued posibility. I had assumed that as the timer display changes when the remote buttons are pressed, that it would be OK.

The T91 I have also has Skoda logo on remote, but I believed that as W-Bus was being used (heater CAN wires not connected) that it would be OK and all speak the same language

I have located the Webasto Thero Test software version 2.15 (newest) but haven't had a chance to try it out yet

I wonder if it's possible to alter the commands issued by T91 using the WTT software if I can get compadible version - otherwise I would be interested in the PCB config that you mentioned TSD - also appreciate the time you put into your response

Failing that I guess I'll flog off the telestart and go with a GSM remote - I see Webasto have an app (for GSM remotes) which looks like a T91 remote..

[TSD]

I had the same (or similar) ideas...

I've only got WTT up to v2.14, but I've not seen a way to change the telestart commands. However there are 32 or 64 bytes of EPROM memory in the telestart receiver that can be fiddled with.

It includes the customer ID, the serial number of registered remotes, and some other stuff. I didn't spot any obvious clues to setting command modes in there.

There are commands for registering and deregistering remotes directly, so possibly there may be one to set operation mode.

There are other commands that are replied to, but always rejected.

When the T91 is first powered up, it broadcasts it's existence on the w-bus, and has a short conversation with the heater and/or timer. Maybe I should revisit that and see if there's any clues in there.

Sadly, my laptop died this evening , so I've got to find and set up something else before I can carry on investigating. (I've got another laptop here belonging to miketomcat, but every time I use that, I just want to beat it over the corner of the table )

I tried dumping the firmware from the processor in the T91, but the copy protection bits have been set. In the portions of memory I could read, I didn't find anything that looked like a command list.

My PCB has already been mentioned here, but I kind of got sidetracked with other projects, and didn't go back to finish it off.

Oh, and No, analog_out does not have to be connected, but it's a handy simple way to control a TT-C, or to turn the interior fan on if your TT-V doesn't have fan control enabled or wired.

[MBE_NZ]

Well I tried out the WTT 2.15 today - loads OK, but still only seems to knows about T100 (in as far as Telestart option availablility on menu)

I disconnected the timer so only T91 was connected to TTV and started diagnosis - I winked and told it that it was T100 instead of T91 - and it echoed something about incorrect length message (yeah I know - I should have captured actual output - maybe next time)

Then I plugged the timer back in and run diag aganst W-Bus

I noticed that when the T91 only was connected - it reported in "Device Info" that the W-Bus version was 3.5 - when the timer was connected it reported W-Bus ver 3 - Hmmm - so am I to assume that "dey no speaka da same linguish"? or is there a solution / way around this?

I'm not much of a techno so maybe I should just be happy with the timer and put the T91 on fleabay. shame really I really liked the idea of using remote - bit annoyed that it doesn't just work

I pushed the "on" button on the remote and the remotes LED blinked away every few seconds for 30 mins, so I believe the Telestart itself is OK - just that it not talking to TTV

I don't suppose there is an earlier version of WTT - that has T91 available under Telestart that someone could provide?

I really don't want to give up yet, but realise that I probably need to succumb to the chance that I don't have the electrical know-how, that things have changed, and it's just not a Holden 70's era straight six like I used to work with... you know - back in the days when weber carbs, extractors and yella terra heads were the standard upgrades? but I digress

[TSD]

Had my T91 running the TT-V (via my pcb) yesterday

My TT-V is currently throwing no-start errors after 3 minutes of running (common problem) so I have to sort that out later on, before I can finish fiddling with the code.

I've got a few more bits to add to the code (fault code reader and fuel pump priming), and produce a pcb with no (or at least, less) mods on it.

I spotted something I missed in my initial 'playing' - the TT-V seems to refuse ALL heat commands addressed from the T91, even one it accepts from the 1533 Timer. It's just possible that simply 'tweaking' the message addressing (so everything appear to come from the timer) would allow a much simpler software load, with full T91 functionality. I'll have to try that out.

Still love fiddling with carbs (wonderful bits of mechanical computing when you get down to it), and always lusted after Yella Terra roller rockers for my Ford V6. The trouble with hacking electronics in cars is all the back and forth between the office to the garage and back every two minutes!

[MBE_NZ]

TSD - interesting to hear you say that you've had some success.

you made the comment that "the TT-V seems to refuse ALL heat commands addressed from the T91" - do you have a Y cable or have you joined in parallel? I believe that the Y cables may connect in series, if so - does the timer interpret / filter the commands in some way maybe??

I was thinking about the commands whilst I should have been sleeping the other night and remembered that the remotes only show green LED when pushing On button - which is supposedly for "Venting" or "Summer Mode". the TTV I have is a "standheizun", which I believe means "unlocked", but when using the WTT software it will run as parking heater PH, and Supplementary heater SH, but the venting isn't avail.

unfortunately I've been unable to date to change the mode on the remotes / T91 to display red LED when pressing on button on remote - which is AFAIK is what they should do for heating mode - is there a way around this? the "press both buttons" on remote doesn't seem to generate any response.

I couldn't help but wonder whether that is where my problems lie - T91 / TTV related problems anyways :-)

the other thought I had was about how clever these things actually are - I'm southern hemisphere and its the winter here, where as T91 came from your side of the globe - but I doubt that would cause an issue with modes. As far as I know the mode would be controlled via the remote button sequence and not by the month...

I cant help but wonder just what the Y cable is deemed a requirement. am tempted to get one, but wonder if I would just be throwing more good money after bad

[TSD]

The Y cable just connects the wbus interfaces from multiple devices - it only exists so that cack-handed fitters don't waste time badly crimping up their own wiring looms with tiny connectors, and then give Webasto a bad rep when it doesn't work.

Every device on the wbus has its own address, and every message includes the sender and the recipient address.

You won't be able to change the mode on the T91 until it's talking to a heater of some sort. I'm not sure if the heater remembers what mode it's in, or if the T91 just won't change mode until it knows what the heater claims to be capable of, but the effect is the same either way.

You obviously have a PC test interface for your TT-V. Does it appear on the PC as a COM port? (I don't know exactly how the Webasto or the ebay interfaces are built - I built my own from scratch.)

If so, you should be able to use it to monitor the messages between the units, and find out whats happening. If you want to try, ping me a PM and I'll try to talk you though it.

[thomas345]

Hi

I just found your posts about T91 and the Disco3/Defender and I have been looking for an T91 solution for my own Disco3 for years now. Is it possible to hear more about your software/hardware solution? I know a bit about C and microprocessors (Arduino), but I simply couldn't figure out the w-bus interface.

I already got the oval timer to start the webasto, but I have not got a t91 yet, because I had not found anybody who has posted a working solution.

Thanks

Thomas

(Denmark)

[TSD]

I'll do a proper write-up if/when I get mine to a 'final' working stage. I don't want to write too many details on the software until I've answered the few questions I still have, so I don't push anyone down blind alleys.

For the hardware I have a small board with an ARM 32bit micro, for no better reason than I already use them elsewhere.

WBus is a simple, open-collector driven, 1-wire serial interface, 2400Bd, 8bits, odd parity, 1.5 stop bits. This should make it trivial to interface to something like an arduino using standard libraries.

For a starting point, all the info you need should be contained within the libwbus project.

[MarkTDiver]

Hi Guys,

 I have been given a V-Top webasto from a land rover not sure which one but I drive a Navara (SORRY) I wanted to know if there is anyway of fitting it into my motor or am I going to have to sell it and get one from a rover 75? Thanks for your time

[MBE_NZ]

Do you know what controller or timer you have? 

If you connect using wbus it should work as can be independent from vehicle system. CANbus totally different story