Hello I have an issue with my LHD 96 355 spider 5.2 , where the hidden 30 amp fuse is constantly blowing, this is currently on a circuit breaker so I need to keep resetting the breaker, it usually trips again less than a minute later. I would like to finally fix the underlying issue. Can anyone help me troubleshoot, I’m not sure where each component is located, I’ve read that disconnecting relay 04269 will rule out the clutch compressor but I’m not sure which relay this is, the manual doesn’t seem to pinpoint this?
Where is your circuit breaker located? The hidden fuse and relays are bolted to the right side of the blower fan/inlet air assembly in the forward luggage compartment. To access them, you'll have to remove the black felt liner (the section near the windscreen). There you will find the fuse and two relays. As you've been told, removing the (aft) relay will stop the compressor clutch engaging. If it's any easier, you could disconnect the plug on the switches on top of the receiver/dryer. This will also stop the compressor operating, but doing this also prevents the LH radiator fan from operating when you turn on the aircon (even though it's on a different fuse). The fan will only operate with engine temperature. I'm not sure I would recommend this for too long, but perhaps for a few minutes it would be ok to help with diagnosis.
The relays are shown in the parts manual, but it doesn't help a lot with the location. Image Unavailable, Please Login The image is shown looking (forward) from the cabin.
Hi Qavion, thanks for the reply first photo is the breaker located in the luggage bay next to the washer bottle, I have removed the felt so assume it is one of those relays, A previous owner fitted the breaker so this is all new to me
It's the two relays by themselves. Normally the fuse is next to them. Anyway, the aft relay is the one. I see another problem with your car. I'm not sure why you have a fuse in the slot next to the relay with the white dot on it. Normally it's only inserted for test purposes (brake system). (EDIT: technically speaking, the relay with the white dot on it is a "diode box", not a relay)
So one of those I’ve highlighted, I’m unsure what you mean by “AFT” regarding the fuse, again this must have been inserted by a previous owner, would you suggest removing or leaving in situ? Image Unavailable, Please Login
It's the one on the left (in the pair you've circled). Remove that yellow 20 amp fuse and keep it somewhere handy, although I don't even think it's the correct value for test purposes. Standby... I'll check.
(EDIT: Sorry, I have conflicting information on that fuse... The Workshop Manual says a 5 or 10 amp should be inserted in position "E" for test purposes). Can you see any wiring attached to that 20 amp fuseholder? Image Unavailable, Please Login I think I need the Teves brakes experts to comment at this point.
Workshop manual procedure for test: Image Unavailable, Please Login I thought my wiring diagrams conflicted with this, but this is correct. Remove that fuse. Sorry for the confusion (If you read my deleted message).
Here's the wiring diagram for the aircon if you need it (5.2 car) https://www.dropbox.com/t/L7pyOUEEzQV4wyhk
Ok so haven’t been able to conclude anything as of yet, reason being I unplugged the relay and had the car on for 30 minutes, the breaker didn’t trip, i then plugged the relay back in for another 30 minutes, again no trip. It’s worth noting, if I haven’t used the car for a while the heater seems ok at first, but then it will trip, and at that point Keep tripping on average within a minute each time, I haven’t been able to use the car for 5 months so I will need to keep persevering with the test. Is there any harm in keeping the ignition and heater on, engine off, whilst the cars connected to a charger? Also, this compressor which I am trying to rule out, is this for the air con? regarding the brake test fuse, I will remove it, thanks for the heads up, I’m assuming it has been relatively harmless having it connected all this time?
I just took a quick look at what Ian sent you (the true value of having friends on Fchat). If you are popping the homemade breaker.....my money is on the compressor since nothing else in the circuit could generate that amp load. As to why....it could be overcharged or it could just be a problem with the compressor. When was the last time the AC was serviced? No one would have gone through hooking up a breaker unless this was a recurring problem.
Hi, thanks for your time according to the cars paperwork, the Air con was serviced in September 2017 Is there a way to determine what the issue with it is, the car will be having the engine out for the cam belts very soon, so if this is a job which would be much easier in that situation I’d like to have it resolved at the same time. If it’s the compressor, is it usually a case of replacing the unit or can it just be a part of the unit which needs replacing?
I can’t say if it has been tried before. I doubt the charger would be able to keep up with the drain on the battery. Yes, or specifically the aircon compressor clutch. The Teves experts may have an answer for you, but I was under the impression that the ABS system wouldn’t activate with that fuse installed. I’m surprised you didn’t get an ABS light, or did the PO remove the bulb
Have you checked if the heater pump is seized? I know when that happens all kinds of other symptoms appear. Anyhow I'll let the pros back at it. Good luck!
The heater pump is actually on a different fuse, Eric. i.e. the aircon system/instruments fuse in the passenger footwell Not even a faulty blower fan or regulator? This is where my knowledge of the system breaks down. The fan regulator controls the speed of the fan and the operating current flows through the regulator, but I don't know what triggers excess current in a setup like this... the fan or the fan regulator? Also, what causes a compressor clutch to draw excess current? Isn't it just an electromagnet. Shorted coils? Surely mechanical problems with the compressor wouldn't cause a fuse to blow?
I believe an easy way to eliminate the clutch is to press the stop button. When pressed the compressor clutch does not engage. Circuit is open I would think.
Very good point, John. No disassembly required. Looking at the diagram, the ECU can only control the compressor via that aft relay and I see no other items powered by the same relay. I did read that the STOP button also closes the hot water valve, but that uses a different power source to the fan and it would only run for a few seconds anyway.
Correct. On the other hand, if the Stop button is released and the temp control is turned to max hot (red dot) the compressor is supposed to be off (clutch disengaged) and the heater valve opened. So there should be a couple of ways to skin this cat, if the manual is correct.
Ok so I’ve driven it to the garage today with the relay removed and the heater didn’t trip the breaker, it would cut out every now and then but come back on after a couple of seconds so assuming it is the compressor, is there a way to test it once the engine is removed, and are they generally repairable or is a new replacement needed?
Did this behaviour seem consistent with the system trying to maintain the selected temperature? By "cut out" do you mean the system gave you cooler air or the fan stopped blowing? To have some idea of what the system is trying to do, you would need to know what the temperatures were inside and outside the cabin. The behaviour varies significantly. I'm not sure how a general mechanic would check the compressor off the car (other than basic clutch engagement and bearing condition). Clutch replacement kits are generally available. Do you know if the compressor is a Sanden? If you knew the model number, the tech might be able to pre-order a clutch kit. Of course, we haven't eliminated wiring faults yet. I guess you could reinstall the relay and disconnect the plug on the compressor to see if the problem comes back.
The Fan would stop blowing, I thought “ah it’s tripped”, however it would come back on a couple seconds later, it did this 2 or 3 times. My next step was going to be reinstalling the relay to see if I could get the breaker to trip again, and then remove the relay again to see if it would again trip, going by previous experience the heater would by now start tripping regularly, although the car has been parked for a while which is unusual for me. I have read the above regarding the stop button, again thanks for the input, however considering I already had the luggage felt up and relay undone I decided to continue with that approach. I haven’t looked at the compressor, I read it’s a pig to get to with the engine in situ,
I don't know if this is normal or not. I don't recall my fan switching off by itself. Was the fan in the AUTO setting? I'm not sure if the ECU is confused by the missing relay. Did you try putting the fan in MAX to give the fan motor and regulator a good workout?
