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Neil Clayton

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  1. I don't know enough to say for sure. The 2k pull up is before the diodes, not after at it would have bee at the board. Other than that I can't say. Before I went ahead, I re-did all the tests I'd done before, and for sure, it didn't work. So I can only assume that the on board resistor (guessing it was a pull up) was somehow different (I have no idea how). All I know is it now works.
  2. So, I got impatient Started by carefully cutting the trace on the board. Verified no connection. Then put 3 diodes in line. This worked, mostly, except when AC was supposed to be off, 4V measured ~0v ish. Guessing it might be floating? I pulled it to 12v with a 2k resistor before the diodes. Everything now works! All fan speeds work, AC compressor is engaged/disengaged, and all turns off when you either turn off AC or switch off fan. Yay. Thanks for the help.
  3. Taken me ages to get back to this, but now I have room to work. Before I cut the track on the ECU or attempt to remove the resistor, wanted to check I'm modifying the right thing. So far, I've been working off this diagram. According to pinouts as per wiring info in Link help, I map DI1 -> 4V = AC Request, and DI5 -> 4AG = AC Switch Before I go further: 1) do I even need to do anything with DI5? I think when I was measuring (the first posts) I hadn't done anything to it. 2) I didn't have DI5 setup as per diagram in initial measures. Might this have thrown off results when measuring DI1? 3) I've seen other diagrams using no pull up/down resistors to the left/right of the diodes (but they might be for g4+ boards). I presume those resistors are still required (especially if I'm about to remove existing pull up from the ECU board)? Or can I leave them off and just go with the diodes?
  4. thanks - if it all gets "too hard" I'm quite happy to write code and slap an arduino on it. it's just that that seems, a little ... extreeme
  5. OK. With 500ohm resistor: Off, 12.54v 1. 1.55v, then 3.54 when AC clutch is OFF 2. 1.8-1.9v. 3.57 with AC clutch OFF 3. 2.85-2.9 (AC clutch never switches on) 4. 2.57-2.62 (AC clutch never switches on)
  6. I will try lower ohms later, got a bit on at the mo. Appreciate the continued replies. v1.2 for both boards as it turns out.
  7. With 1.5k fitted to ground, and car running: Fan speeds, v reading: 1. 1.65 2. 1.90-2.12 3. 3.01 4. 2.8 same as before, fans 1/2 works, fan 3/4 not (guessing it has to be ~below 2v)
  8. after or before the diodes? I've tried after, (1.5k, 10k and 20k) and this results in similar behaviour. The voltage is pulled a little lower with less resistence in circuit, but still ~8 -> 10v across all fan settings. I'll remeasure today; but when off the resistence between (before diodes) from ACReq -> ground is about 2kOhm. I'll try with car on to see if this changes as well.
  9. Hi, Trying to get aircon working on an FD3S with a v1.2 board G4. AirCon Req (DI1) is set to LOW, with pull up OFF. If I connect the signal directly, I get: Off: 13.9 1: 1.6v 2: 1.7 - 1.9v 3: 2.9v 4: 3.6v and, as others have seen, AC works on fan1 and fan2 only. So. Diodes. If I put two diodes (1N4148) in series... nothing works. Diagram is: ECU <- |--- <- |--- <- DI/ACReq from loom. where |--- is the diode. (black band towards ECU) The signal current is 8.4ma. I read the same 1.6v (etc) on the non-ecu side of the diode pair, but the ECU side just reads 12v. I've tested the diodes and there's an expected 1.2v drop across both in series. So I don't understand ... it's like the diodes arent working. Or the signal isnt getting through. I've tried pulling the ECU side to low via a 22k resistor (only cos I saw that on another diagram, not because I know what I'm doing). no change. Any help / tips?
  10. "still wires connected to the RS232 pins you will lose comms" - do you mean, even if those pins aren't connected to anything? They are attached to the ECU PCB @ the PCB, and go to the female (black) comms plug, but there's no electrical connection to anything RS232. i.e: the male plug connected here has been chopped up, and only has green/white CAN lines electrically connected to anything. I would have thought there would be no difference in leaving those RS232 lines disconnected @ the plug (male side) vs disconnecting at the ECU PCB itself. Are you saying that I need to physically disconnect the RS232 pins from the ECU PCB? The dash itself is a black box, with no configuration. It's fine if I cant get it to work with the G4, it was an experiment after all. Still, I'd like to know if I'm supposed to be able to run a CAN BUS and have my laptop also connected to the G4 while doing so (two different connectors; CAN on the black one; USB to the laptop on the red other one)
  11. Right, sorry - I didn't mean to confused with ODB2. The dash, I assume, is using the CAN H/L of that connector. That's what I'm trying to make use of anyway; OBD2 is only a part of this because of that physical connector. I've disconnected the RS232, and I'm only running the CAN H/L lines from the comms connector. I *was* previoulsy using RS232 to read from the dash, but havn't used it for a number of years now and havn't revisted that old project. At the time of writing; the RS232 connection from removed/disconnected from that same cable. The PCLink is connected via the 2nd USB connection (red ringed connector) cable to the ECU.
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