Radiator fan & A/C not working~any help appreciated

[okehdokeh]

This is bound to have been covered before but thought I'd ask afresh. I have a 2003 2.0 HDI executive estate that the aircon has gone down on, there are no volts at the compressor electromagnet plug when A/C is selected on dash and the radiator fan does not kick in even when the engine temp is above 90 degrees. I have swapped out the engine coolant temperature sensor (thermostat housing one) thinking maybe there was no signal going to the BSM/BSI/ECU but nothing changed.

I removed the radiator fan and checked that it was working on an independent power supply which it was, I also checked the compressor clutch on an independent power supply and it operated fine.

All the push together connectors have been gone through and cleaned as have any relays on the BSM, the relays were checked for correct operation including the grey recall fitted fan relay clipped to the battery box.

I cannot find the aircon pressure sensor, is this tucked away somewhere under the battery box? Unfortunately I do not have access to PP2000

The system was re-gassed last year but the pressure was correct before re-gas.

If anyone is in the Hinckley, N.W. Leicester area who could put PP2000 on it for me I would be more than happy to pay them or anyone who could point me in the right direction and where to look next would be really appreciated.

I have had the car since 2015 and love it so really do not want to cook the engine

Thanks, Paul

[Wul]

I'm not familiar with HDI engine and it's cooling system, does it have resistor and/or relay beside the radiator fan?


Over here if a Peugeot has radiator fan problem most of the time it was caused by either bad relay or resistor.

[Doggy]

On post 2001 HDI's the engine ecu manages the a/c, controlling the radiator fan speed to regulate the condenser pressure - it doesn't simply switch the fan on whenever the a/c is running like earlier cars.

It sounds like the ecu is not permitting the compressor clutch to engage, most likely cause is low gas pressure.

While the pressure sensor LOOKS identical to the 'pressostat' fitted on earlier cars, on these models it's a pressure transducer which allows the ecu to measure the actual gas pressure.

[okehdokeh]

Thanks for the guidance Doggy,I don't see any signs of leakage on the A/C system or burning on the ECU so thought it was going to be the pressure sensor. I checked the multi connectors on the sensor and the other one clipped to the rad housing and these both looked ok.
I intend to keep the car as long as possible so really need to get pp2000, I have an icarsoft CP11 scanner but that doesn't show any faults in this case.

I will get the A/C pressure checked next week, if pressure is ok I guess the system will need to be purged before removing the pressure sensor if it turns out to be faulty ?

Thanks again

[Doggy]

Not sure. My first HDi had a non-return valve - it was screwed into the sensor hole in the condenser and the sensor itself screwed into that. This might help: viewtopic.php?f=10&t=7606

TBH I can't see it in the pictures and it was about 12 years ago. I think the valve if present is meant to allow you to change the sensor without losing the gas. I changed the condenser on my second 406 about 5/6 years ago and don't remember whether it had a valve or not.

If it was mine, I would briefly depress one of the filling valves to see if it still has gas as a first step.

[okehdokeh]

Thanks Doggy, that's going to help me a lot I think. Knowing that there is a non-return valve under the pressure sensor is a relief, especially if the system is still up to pressure and it's just the sensor that's gone.

Your previous postings on this are really helpful and very much appreciated, know I have something to work with. Thanks.

I'll post up tomorrow with any progress.

[Doggy]

Be careful.
I can't guarantee yours will have a non-return valve.

[okehdokeh]

Dodging the rain showers I managed to check that the A/C system had pressure using the method Doggy suggested, a quick press on the valve pin and a strong hiss suggests that the system has pretty good pressure.

With the engine running and the interior blower on low speed pressing the aircon dash button failed to engage the pump clutch and or turn on the rad fan. Next I disconnected the two pin plug (engine still running) and checked for volts here but there wasn't any so put an independent power supply to the clutch and hey presto the clutch engaged, the rad fan came on at low speed and nice cold air came out the interior blower.

Without proper diagnostic equipment I'm clutching at straws a bit but thinking it's probably going to be the pressure sensor on the condenser, then I'm thinking that must control the low speed fan actuation and if the fan kicks in the sensor must be ok. It's all too much for my ageing brain

[Doggy]

Well done, you're making progress.
Trying to think what else would stop it working?
Just remembered some people have had problems with the relay in the BSI that controls the clutch.
Another possibility is the evaporator temperature sensor - this was faulty on one my bro had a few years back, we never did get access to it.

Does your car have climate control, or just on/off a/c and is there an indicator to say the a/c is on?

You really need a PP2000 session to find out what's going on. I would happily do it for you, but I'm about 40 miles away.

[okehdokeh]

Thanks, yep little moments of success but I may just take you up on your offer if at the end of the week I/we haven't cracked it by then. The A/C is plain on/off with a button on the centre console, an A/C symboI lights up when switched on. I tried a spare unit to be sure it wasn't the switch playing up but there was no difference.

I'm guessing this is a full MUX model so would the clutch relay be on the BSM circuit board instead of the main BSI or engine ECU? Thanks.

[Doggy]

I would expect it to be in the BSI as this example viewtopic.php?f=10&t=20802&p=207063&hil ... ay#p207063

Unfortunately I no longer have access to the wiring diagrams so can't help you locating the correct relay.

I suggest you check you have an effective ground connection at the clutch before pulling the dash to bits.

I would certainly want to prove the relay coil was energising, all fuses are OK and if at all possible verify 12V supply available at one relay contact and continuity between the other and the clutch connector, before attempting to swap it.

[WillNZ]

It is dark here right now. Will take a photo of the BSI in one of my many 406hdi's tomorrow which has the mod to replace the faulty relay in the BSI. Have had this fault in about 6 of them so far, it is easy to remove and replace relay with an external more substantial one.

[okehdokeh]

Thanks Will, that'd be appreciated. My BSI is the same as the picture I've attached, the other picture of the cut open BSI is the same type as mine that I found on this forum and was trying to figure out what relay was the A/C clutch one. I had been told by someone that by 2003 Peugeot cars that were semi or full MUX had the A/C clutch relay in the BSM under the bonnet, I guess this isn't correct?

I really appreciate you guys helping me out on this!

[okehdokeh]

The BSI same as mine...........

[okehdokeh]

Fuse F feeds the console with the A/C switch so it looks like the circled relay in this picture could well be the culprit.