A.C Issues - Help please
Discussion
Hey all. Firstly let me introduce myself. I am James, from New Zealand. My father in law has a TVR Chimaera imported from Japan. As he is kept busy with his two mustangs the Chimaera sits in the garage and does not receive the love it deserves. I made this comment to him and his answer was to throw the keys at me. I am now the caretaker and super excited driver of this piece of automotive art.
In a month my wife and I will be taking it for a Mad Max themed cannonball run, ending with laps at Pukekohe Raceway. I promise pictures and videos if someone can help me with a little issue. Tbh, I will probably throw up some pics and vids anyway, but don't let that stop you from helping if you can.
Vehicle specs;
1996 TVR Chimaera 500.
Issue;
When I turn on the air conditioning, the AC pump runs as it should, but the fans do not. If I manually over-ride the fans, I get nice cold air (ie; the ac works as it should). Only problem with that is if you forget to override the fans and turn the AC on it will overheat and cook the unit, also it means I have to have the wiring loom exposed)
When the car first turned up the relays for the ECU and Fuel injection were the wrong type which resulted in the battery going flat. We replaced them and no longer have that issue.
This makes me think that perhaps there is another relay that is wrong, or missing completely, that should turn on the fans when the AC is turned on.
If you have a similar model and could have a look at the fuseboard and additional loose wiring loom and maybe take a few photos and/or list a few part numbers for the relays you find it would be a huge help.
Any other info or suggestions from people who have had similar issues will be much appreciated also.
And to beat anyone to it - yes I realize it is a convertible and the best form of AC is the top down, but seeing as it has the AC installed I may as well get it working :-)
In a month my wife and I will be taking it for a Mad Max themed cannonball run, ending with laps at Pukekohe Raceway. I promise pictures and videos if someone can help me with a little issue. Tbh, I will probably throw up some pics and vids anyway, but don't let that stop you from helping if you can.
Vehicle specs;
1996 TVR Chimaera 500.
Issue;
When I turn on the air conditioning, the AC pump runs as it should, but the fans do not. If I manually over-ride the fans, I get nice cold air (ie; the ac works as it should). Only problem with that is if you forget to override the fans and turn the AC on it will overheat and cook the unit, also it means I have to have the wiring loom exposed)
When the car first turned up the relays for the ECU and Fuel injection were the wrong type which resulted in the battery going flat. We replaced them and no longer have that issue.
This makes me think that perhaps there is another relay that is wrong, or missing completely, that should turn on the fans when the AC is turned on.
If you have a similar model and could have a look at the fuseboard and additional loose wiring loom and maybe take a few photos and/or list a few part numbers for the relays you find it would be a huge help.
Any other info or suggestions from people who have had similar issues will be much appreciated also.
And to beat anyone to it - yes I realize it is a convertible and the best form of AC is the top down, but seeing as it has the AC installed I may as well get it working :-)
Hi James, My 95 chim 500 is also from japan and has ac (which I wouldn't be without) it also had exactly the same problem as yours which i realised was not good. i cured mine by fitting a relay that powers the heater fan on low speed when the ac is turned on then if you want more air you can turn the switch up as normal. My system has obviously been modifyied from standard there is a micro switch on the heat control wheel that has no wiring going to it? I assumed that if you wanted ac you had to turn the control to full cold which would trip the switch and turn it on (maybe). I use ac to demist the screen in the winter so if this is how the original system worked then I can see why someone has modified it. Also the switch on the dash looks a bit out of place there I think it has been added. I wonder if yous has had the same "mod" as mine? If you had the dash top off you could check the micro switch ill put some pictures up when I go to my shed later (my dash top is off at the mo.)
Hi, thanks for prompt reply :-)
You are right in thinking that switch on the dash is after market. This is what mine looks like;
Let me clarify;
When AC is turned on the blower fan does not turn on automatically, but can be turned on with the lower wheel (which is fine, but it does seem that it should turn on automatically)
It is the 2 main radiator fans that do not turn on automatically when AC is turned on.
This is my wiring loom;
We found (quite by accident) that if we bridged the two points shown in this photo the radiator fans switch on. It looks like there should perhaps be a relay that plugs in here? This is the black plug right at the end of the loom.
You are right in thinking that switch on the dash is after market. This is what mine looks like;
Let me clarify;
When AC is turned on the blower fan does not turn on automatically, but can be turned on with the lower wheel (which is fine, but it does seem that it should turn on automatically)
It is the 2 main radiator fans that do not turn on automatically when AC is turned on.
This is my wiring loom;
We found (quite by accident) that if we bridged the two points shown in this photo the radiator fans switch on. It looks like there should perhaps be a relay that plugs in here? This is the black plug right at the end of the loom.
Well for a 3rd different picture of a Japanese Chimaera 500 with a/c mine looks like this.
For mine the a/c is engaged by a micro switch activated by moving the bottom wheel all the way over to the right. Fan speed is controlled by the dial just to the top right of the 2 wheels, they are switched on/off by pressing the dial. I am not 100% certain but I think mine does not come on automatically when the a/c micro switch is engaged.
Will be the weekend before I can get back in the garage and hook the battery back on to check.
Also my recommendation is replace all your fuses with smart fuses, was having a short in my car I did not know of until I did this.
For mine the a/c is engaged by a micro switch activated by moving the bottom wheel all the way over to the right. Fan speed is controlled by the dial just to the top right of the 2 wheels, they are switched on/off by pressing the dial. I am not 100% certain but I think mine does not come on automatically when the a/c micro switch is engaged.
Will be the weekend before I can get back in the garage and hook the battery back on to check.
Also my recommendation is replace all your fuses with smart fuses, was having a short in my car I did not know of until I did this.
James Beck said:
Hi, thanks for prompt reply :-)
It is the 2 main radiator fans that do not turn on automatically when AC is turned on.
This is my wiring loom;
I know nothing about TVR AC, but it sounds odd to me that just because you turn on the AC, that the radiator fans should come on??It is the 2 main radiator fans that do not turn on automatically when AC is turned on.
This is my wiring loom;
Surely the radiator fans only come on when the coolant reaches the required temperature
Hi,
I've trawled around the A/C on my TVR after previous owners had made some minor mods, so have a good idea how the A/C electrics work. Quinny is correct if the TVR system has not been messed with.
The trinary switch on top of the reciever/drier will switch the rad/condensers fans on and off depending on pressure in the A/C system. If your system is working and the fans are not switching then the trinary switch maybe at fault. The trinary switch also shuts down the A/C system if the gas pressure is too low or too high to prevent damage. Note, the rad fans are also switched on and off by the engine coolant otter switch.
Ozstyle.
I've trawled around the A/C on my TVR after previous owners had made some minor mods, so have a good idea how the A/C electrics work. Quinny is correct if the TVR system has not been messed with.
The trinary switch on top of the reciever/drier will switch the rad/condensers fans on and off depending on pressure in the A/C system. If your system is working and the fans are not switching then the trinary switch maybe at fault. The trinary switch also shuts down the A/C system if the gas pressure is too low or too high to prevent damage. Note, the rad fans are also switched on and off by the engine coolant otter switch.
Ozstyle.
James if its any help I suspect there should be a relay in that socket, mine dosen't have one in it but the purple/black and black wires to the socket have been cut and extended up to another relay attached to a temperature adjustable "Run Max" after market fan controler. (Which takes its readings from temp switch near the thermostat not in the swirl pot as standard)
There must also be an ac controler somewhere which takes a temp. Reading from a probe in the evaporator and commands the ac clutch and fans accordingly. I have not found this controler on mine yet so can't offer any further info on that. Good luck.
There must also be an ac controler somewhere which takes a temp. Reading from a probe in the evaporator and commands the ac clutch and fans accordingly. I have not found this controler on mine yet so can't offer any further info on that. Good luck.
I started my car from cold tonight and switched the ac on, the ac clutch engaged but the cooling fans did not run. I left it running and it was around 1minute before the cooling fans came on. Just make sure that this is not what you are seing we could possibly be chasing a problem that dosen't exist. (Wishfull thinking).
Anyway the two wires that you have bridged are the same wires that are cut on mine and go to a relay that is triggered by the Runmax controler, joining these two wires triggers both fan relays which on my car are in the fuse box bottom left below the headlight relay. The fuel pump, ecu, both ac relays and both cooling fan relays all seem to be the same in that they all connect pins 30 and 87/87a when activated (these pins not parallel to each other but at 90 deg. To each other)
Anyway the two wires that you have bridged are the same wires that are cut on mine and go to a relay that is triggered by the Runmax controler, joining these two wires triggers both fan relays which on my car are in the fuse box bottom left below the headlight relay. The fuel pump, ecu, both ac relays and both cooling fan relays all seem to be the same in that they all connect pins 30 and 87/87a when activated (these pins not parallel to each other but at 90 deg. To each other)
dazee said:
Well for a 3rd different picture of a Japanese Chimaera 500 with a/c mine looks like this.
For mine the a/c is engaged by a micro switch activated by moving the bottom wheel all the way over to the right. Fan speed is controlled by the dial just to the top right of the 2 wheels, they are switched on/off by pressing the dial. I am not 100% certain but I think mine does not come on automatically when the a/c micro switch is engaged.
Will be the weekend before I can get back in the garage and hook the battery back on to check.
Also my recommendation is replace all your fuses with smart fuses, was having a short in my car I did not know of until I did this.
I have this layout in my '99 Chim 450 with factory fit AC. Again the AC is engaged by turning the TOP wheel over to maximum cold. The blower fan must be turned on manually by pressing the fan speed dial. The radiator fans cycle on their own presumably according to the condenser temperature. The AC clutch also cycles on its own according to the air temperature - as the AC clutch engages, the ECU tells the engine to up the revs a little from idle to presumably compensate for the additional load.For mine the a/c is engaged by a micro switch activated by moving the bottom wheel all the way over to the right. Fan speed is controlled by the dial just to the top right of the 2 wheels, they are switched on/off by pressing the dial. I am not 100% certain but I think mine does not come on automatically when the a/c micro switch is engaged.
Will be the weekend before I can get back in the garage and hook the battery back on to check.
Also my recommendation is replace all your fuses with smart fuses, was having a short in my car I did not know of until I did this.
The black relay socket with dark green face is part of the Rover loom, I don't believe TVR ever fitted a relay here. The Rover loom uses a relay that activates the rad/condensor fans for about 10 mins after the ignition is switched off, but only if under bonnet temperatures are high, temperature measurement using the fuel rail temp sensor.
The TVR heater box has an A/C evaporator temp switch attached to its side with a probe running into the evaporator matrix, the switch does not seem to be ajustable. I assume this will turn of the A/C if the evaporator starts to ice up.
hope this info helps.
The TVR heater box has an A/C evaporator temp switch attached to its side with a probe running into the evaporator matrix, the switch does not seem to be ajustable. I assume this will turn of the A/C if the evaporator starts to ice up.
hope this info helps.
Just looked at a pin out for the 14cux, it looks like ac is controlled by it. pin 36 goes to a thing called a condenser fan timer AMR3678 which looks like it plugs into that empty socket that you have bridged to bring the fans on. Would need to check the wiring but sounds right.
Just google AMR3678 relay. Just read ozstyle,s post explaining that this relay may not have ever been there so disregard my guess work.
Just google AMR3678 relay. Just read ozstyle,s post explaining that this relay may not have ever been there so disregard my guess work.
Edited by NZ fan on Tuesday 28th January 00:25
Edited by NZ fan on Tuesday 28th January 00:27
The ac condenser is the same approx. size as the radiator but not as thick, only one row of tubes. If you have your grill out to clean your air filter you will see it. Looks just like the radiator (because it is a radiator I suppose). It must surely hinder the cooling to some extent, especially when the times you really want the ac on is when it's a stinking hot day. Not sure if the engine radiator is any larger than normal to allow for this? It's not uncommon nowadays to see three or four radiators stacked up in front of each other, inter cooler, engine oil cooler, auto trans. Cooler, ac condenser then the poor old engine rad gets the pre heated air from that lot.
Thanks. I was thinking surely covering the entire radiator by another radiator would not help the car cooling, and now toying with the idea of just removing the a/c altogether. In almost 2 years I've had the car the a/c was only fixed a couple of months ago, so not like I'd miss it. Everywhere I go it's in the way!
Next question.....what grill?
Next question.....what grill?
My car is an early one (95) and it has a mesh grill. I forgot about the later cars with the horizontal bar, I have never actually seen one of the later cars in the flesh. I suppose tvr removed the mesh to improve air flow. Re. Removing your ac I think it's down to what you use the car for, if you are doing track days then I suppose it would help and as you say more room for working.
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