Renault Laguna 1.6 16V, 1998-05 (facelift), engine K4M720, 135.000 km.
Symptoms and procedure:
Cheers!
PS: Of course, I'd be grateful to those more experienced visitors of the forum who have to add and/or correct something here, to improve the story.
Thanks.
Symptoms and procedure:
- When aircon control switch get pressed, the light indicator goes on/off correctly and the engine slightly changes RPM, what proves that the system draws a significant amount of current, but I couldn't hear any click, neither from relay nor from the clutch.
- Before aircon definitely died, there appeared several intermittent breaks in operation (for about one minute or less).
- Under-bonnet aircon pipes are warm.
- The cabin fuses (at driver footwall) and under-bonnet fuses (at the most left car side, under the vertical plastic cover) tested – all fuses ok.
- Most of relays tested by interchanging their positions (of the same type and value) – all tested relays are ok: two relays under the bonnet, and several relays at underside of the cabin fuse box (picture #01). However, I actually don’t know which relay pertains to which function; I have Haynes manual, but cannot find such information there; moreover, it appears that this version of Laguna is different in many details from what could be found in Haynes or on the web.
- Tested the voltage at the heater/cooler blower motor connectors (bottom of the motor case), what showed the odd thing: at the very beginning there was 12 volts just for a couple of seconds, but then dropped to almost zero (about 0,5 volts). I really couldn't explain this and decided to take off the motor by releasing four screws from the bottom of motor case (picture #02) at the passenger footwall. Motor tested by wiring it directly to the battery and this approved that motor is ok (picture #03).
- Tried to inspect contacts on control unit (manual type). Dismounted the radio by applying the handmade tools (3 mm wire) into four holes on the radio panel (see picture #04), pulled out the ashtray (picture #05) and removed the storage tray (picture #06). Eventually came up to the aircon control unit (picture #07), but then get stuck – couldn’t remove it; it seems me not intuitive at all and I missed the instructions for this removal. Perhaps it might be necessary to remove the whole dash before (?).
- Now tried to inspect the resistor pack. In fact, from some web posts I've made inference that the resistor pack might be the culprit ONLY if the blower is NOT WORKING ON SPEEDS 1, 2 AND 3, and DO WORK ON SPEED 4. But this proved not to be true, and I understood that when I realized that the blower motor is actually connected by only two wires, both coming from resistor pack; therefore there is no separate power source to blower motor, bypassing the resistor pack and to provide for operation at position 4 of aircon control switch (maximum blowing speed); consequently, appears that the resistor pack might have a critical impact to blower functioning at ANY speed! Hopefully, after all tries mentioned above, the resistor pack remained me as the only acceptable possibility for further investigation, so I dismounted the pack. However, here I had firstly to remove the glove box: three screws at the upper side and three at the bottom side (under the felt pad) of the box aperture (see at http://www.renaultforums.co.uk/showthread.php?t=5107&highlight=resistor). When glove box was removed, I've been able to access the resistor pack (picture #08). To dismount it, two big connectors (blue one in foreground, and black one in the background) from the top of resistor pack had to be pulled out, just to get enough room for pulling out the resistor pack itself (picture #09). Additionally, the red and black wires, coming from the blower connectors to resistor pack, needed to be disconnected. When I had the pack in my hands and fully dismounted, I carefully cleaned it with alcohol and analyzed the soldered joints by using the ohm/volt meter or visually by using a magnifier. Thus I found that one of soldered points under the magnifier seemed to have broken solder, why it was very dubious (picture #10). I carefully re-soldered it (picture #11), mounted in place and tested again the voltage at the motor connectors. Now I've got correct and stable values of about 12.30 volts (picture #12).
- I hope you can imagine my joy when, after putting all things in place and switched on the aircon, I found that it really works again. What a relief! The triple one:
- Hooray! I have the cool air again! Really big deal when the shade temperatures out there rise up to 40 °C.
- I surely saved a nice amount of money. I recall the very similar case ten years ago with my older Laguna 1994, when I lost the heater blower at winter time with minus 18°C. Had been very busy with no time to spend in such investigations, and one of local garages asked about 1.600 EUR to repair it (!!!). Certainly, I was very pleased when another dealer resolved my problem for "only" 200 EUR.
- Finally, it's a really good filling, after wrestling for several days with such a problem, when you finally win the battle.
Cheers!
PS: Of course, I'd be grateful to those more experienced visitors of the forum who have to add and/or correct something here, to improve the story.
Thanks.