Peugeot 406 HDI water in driver footwell - billscot
A few months back noticed some water in spare wheel housing, drained, looked for source, assumed via boot or rear window seal, although no signs of damage. A couple of weeks back, similar situation plus some strange messages on Multi-function display, such as "Economy Mode", but nothing electrical, like radio, left switched on, strange! Last week, left stranded, car wouldn't start, battery dead. AA discovered driver side footwell swimming in water, hence electrical probs and strange Mf display.
Can't work out if water is coming in at boot and getting to front or vice-versa. Help, any ideas? Have heard that Peugeot useless, and very expensive at "diagnosing".
Peugeot 406 HDI water in driver footwell - Saltrampen
Check the obvious, like Bulkhead plugs and grommets (ie where the cables and wiring go from engine into Bulkhead). Check bottoms of all doors for wet trims (Membrane leaks).

Dry the interior out, remove all mats. Stay inside car whilst a friend gently sprays a hose a one section at a time for several minutes, wait a few minutes, then inspect. Make sure you train the water on the sunroof, side windows, light clusters, rear hatch, doors and main windscreen - these are the common areas that could leak.
IF after a thorough dowsing, gentle bounce rear and front of car to dislodge any water that maybe sitting somewhere inside. Also covering the the dry car interior carpets with newspaper will show prescence of water and possibly direction of leak , if you have a dark trim.

- This is what Peugeot did for me many years ago and discovered a faulty sunroof.
- To be fair any Garage will take an hour or more to do this so might charge for this especially if the final repair is cheap. Depends on how much they value your long term custom as well.
Peugeot 406 HDI water in driver footwell - LeePower
Boot mounted cd changer?

406 saloon?

Its the rear light seals leaking, well known fault.

The odd electric problems & warning messages are because the cd changer or its plug has got wet & your CAN system doesnt like it, fix it quickly & seal the rear lights up before you do some serious expensive damage by blowing your BSI up.
Peugeot 406 HDI water in driver footwell - billscot
No boot mounted CD changer but, suspect that rear light cluster(s) might be source of trouble. I'll give back of car a good hose soaking and check for signs of water in boot. I should have mentioned in original message that water is getting in irrespective of whether car is driven or not. Discovered more water other day after "drying out" and leaving car standing over night in heavy rain!
Peugeot 406 HDI water in driver footwell - billscot
Thanks for the suggestions. First dry day (hopefully) this week. No sunroof so one potential source eliminated! From lifting driver footwell carpet (what a hassle), water appears to be coming from rear of car to front, maybe via a sill? Can't understand how it has suddenly started "flooding", noticed that driver side rear light cluster has some water ingress and signs of water on driver side of boot near wheel arch.
Peugeot 406 HDI water in driver footwell - billscot
Just to confirm and save anyone else from the hassle that I had with the water ingress to my 406 HDI. It was indeed the rear driver side light cluster seal that was at fault. It'd been incorrectly refitted (I'm certain) following a bulb replacement during an MOT test at a well known chain of tyre and exhaust specialists! Discovered it by removing all boot cladding, hosing car down from roof towards the rear and peering into boot from back of car (rear seat backs folded forwards) using a torch. It was dripping into car from around the light cluster. What an appalling design fault that such a small displacement of the seal can result in such water ingress and all the subsequent consequences! Thanks for all the helpful tips and suggestions.
Peugeot 406 HDI water in driver footwell - LeePower
Rear light cluster seals are a well known 406 fault in the trade, water plus the later 406s multiplexing system is electrical knightmare time!
Peugeot 406 HDI water in driver footwell - 232burn
start hose testing from a single panel bottom upwards ! otherwise as ever water runs down leaving you guessing
Peugeot 406 HDI water in driver footwell - LeePower
Even if you dont have the boot mounted cd changer fitted, seeing as PSA use a standard cabin loom on each model of car it will most likely still have the plug for it on the loom tucked away in the left hand corner of the boot, blue square plug.
Peugeot 406 HDI water in driver footwell - azazel

I have water in the rear of my 406hdi estate

My car was having windscreen misting up problems to such a point that I was having to open the windows to see, and have the windscreen demister on full blast. My aircon stopped working long ago. I thought the flap was stuck for resirculating air but that was fine. Replaced pollen filter (where flap is clearly visable with filter removed) also but the problem remained. Next I checked the outgoing vents at the rear and thats when I discovered large amounts of water in the boot area.

Im pretty sure that it comes in through the seals of the vents behind the panels either side where you gain access to the rear light clusters. The water gets in through spray from the rear wheels and then fills up and runs through part of the chassis at the rear of the car contaminating both sides. The high humidity causes condensation problems which forms between the roof and the lining and then water runs down around the light cluster wiring on the other side. This was misleading me into thinking that the roof bars were leaking or the light cluster but on inspection they appear to be sealed.

The rear of my car got damaged on one side which may have damaged the area arround the vent seal. The metal there is very thin and easy to straighten or bend. I removed the vents and cleaned them, siliconed the seal in and then siliconed the fitting into the car. This seems to have done the trick.

I hope this helps others as the symptoms can be quite misleading of the cause!