Without wanting to jump on the bandwagon would you rather do it on an exige with a knackered aircon? Say someone who doesnt mind things being tested on the car …
( see where this is going? )
I’d be more than happy to experiment on your car next time the clam is off! Might be a good opportunity to either fix your AC, or rip it out completely depending on your preference.
I do think I can get the bypass in and working without removing my clam or the AC, it would just be significantly easier if this was all up on the bench.
That could be useful. Ill need to remove the rear and front clam I think though and call your man that can for the pipework. I think most of it is FUBAR.
I would love to have it working!
Yeah first job is probably a pressure test, didn’t you say you’re down a compressor too? Unless you know for sure a pipe is leaking, I’d just be getting it tested first - could save you a whole lot of headache if it turns out you just need a new compressor!
I was, but replaced it with a known working one. Wiring is disconnected ( to avoid stuck clutch ) but some other pipes are dead and have been removed. I lost all my refrigerant from the pipe near the flap thing. Heard it pssssttching and confirmed with a test
[quote=andybond post_id=241617 time=1593258409 user_id=27847]
I was, but replaced it with a known working one. Wiring is disconnected ( to avoid stuck clutch ) but some other pipes are dead and have been removed. I lost all my refrigerant from the pipe near the flap thing. Heard it pssssttching and confirmed with a test
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I’m with you. I think we’ve discussed this before but the Lotus AC system is something I could happily live without if an otherwise perfect car was on the market for example, but when you’ve got it and it’s tantalisingly close to working properly I very much would like to keep it tip-top. There’s definitely a cut-off though, if/when my sill pipes go I’ll be hard pushed to justify the effort to restore them… if facing a total overhaul like you, it would be a tough thing to justify compared with saving 10kg and binning it all off!
Anyway, back to my plans - I took delivery of a spare actuator yesterday so I setup a quick test rig with that on the bench. I can confirm that when the actuator receives the 12V from the ignition live but nothing on the “control wire”, it defaults to the hot position as we would expect.
Further to that, I hooked up my multimeter to the wiring loom to confirm the wire colours but also to see what the operation looked like, took a video here:
Testing heater flap wiring - YouTube
When set to full cold the control wire (yellow) shows 0.25V (ish) and when set to full hot it shows the full power of 12V ign (14v with car running).
So combining these two tests would suggest 0V = Hot (disconnected control wire), 0.25C = Cold, 12V = Hot, 6V = 50%.
I couldn’t really test much more than this as for the life of me I couldn’t replicate the problem today, the flap behaviour impeccibly. What I hope to see is the flap go unexpectantly to hot, then take a reading on the control wire as close to the actuator that I can - if it shows 0V, then I know I’ve got a wiring issue, if it shows 0.25V then I know the problem is inside the actuator itself.
If I can’t replicate in the garage, then I think my next plan is to make up a 3-4ft piggyback harness for the actuator so I can run a test lead into the car and go for a drive with the multimeter connected.
I’m sort of hoping the actuator is at fault, as then I can proceed with the bypass mod knowing my wiring and knob is all in order. If the fault is somewhere in the wiring then I’m really limited as to what I can do as it just vanishes into the loom… so might have to run some extra wires back to the dash just to bypass the loom. :roll:
Oh and my phone has stopped auto orientating into landscape, so really sorry for portrait video… 
Hi guys, sorry don’t post to often on here
If you pm me your email I have a colour wiring diagram I can send over
I have checked this against my car and appears to be correct
Edit: here’s a pic of the fan/air con diagram
Untitled by Jamie Milling, on Flickr
I was reading this with great interest as the aircon has never worked on my S1 Exige. I’ve just finished a study of the manual and was amazed to discover it has a cut off valve on the hot water fitted as standard!
Big thanks to Jamie for sending over the coloured wiring diagrams - big help!
As part of the work I intend to do I’ve picked up a Lotus thermostat upgrade kit for the AC, it’s not related to the root of my issue but once I fit the matrix bypass access into the HVAC area is going to be impeded even further, so now is the time to do it.
Actually, December was the time to do it when my HVAC system was on my workbench, but I didn’t have awareness of the thermostat kit back then. In short the system fitted to 06 and earlier cars was an analogue switch, which would disable the AC cycle only after the evap unit had frozen over… you’d then need to wait X minutes for it to natually thaw out before AC would kick back in again. I don’t believe I’ve experienced these symptoms yet, but as above I wanted to rule it out.
The new kit is a digital thermostat, I guess with a more granular control. Lotus fitted them from 07 onwards and it’s a drop in replacement, just need to extract the thermostat probe from the HVAC box, snip it off and then 3M tape the new unit to the top of the HVAC box and poke the new probe in. The instructions claim that this is only possible on LHD Elises with the clam in place, RHD Elises and all Exiges are impossible to do with the clam on… but based on the time I’ve spent in there, I beg to differ so aim to prove otherwise.
An added bonus of the new kit is that it replaces part of the wiring harness for the heater blend flap (the part I’m struggling with), so rules out another short piece of wire and 2 plugs as being the source of my problem. The new harness allows the thermostat to take power (the original doesn’t need it) for operating.
I have a bit of wiring to do, then I’m ready to do a bit more testing on my system. I need to rule out the wiring loom and the potentiometer knob as being my problems as it’s pointless leveraging them for a bypass valve control if I’m just inheriting the same issues… once I can prove the wiring to be sound, I’ll crack on with the bypass.