viking

I successfully changed the heater matrix over the weekend. Spent Saturday and Sunday 08.30 to 19.00 on both days to complete ! Had a few moments when I thought I'd been defeated but managed to win in the end. The wiper gear needs to be removed, steering column unbolted / moved down to give clearance to remove facia. Facia cross member strut needs to be unbolted and shifted forwards about 3" to allow the heater unit box to shift forwards. This allows the heater matrix pipes to clear the bulkhead. The heater box need not be removed as the matrix slides in through the top. The matrix I bought looked the same as the old unit but did not fit in. There was a lip around the top preventing it from sliding fully home. Ended up modifying the top of the box. Just needed to remove some plastic around the top. Delayed the job for an hour and a half. The awkward stages were removing the steering column shear bolts. No clearance to get a drill in straight. I propped up the facia with a block of wood. This gave enough space to get a hammer and cold steel chisel in to knock the bolts round. They're not so tight. I was able to re-use the bolts again, just nipped them up using same method. The 10mm nuts (3 in all) holding the heater box to the bulkhead were very awkward to remove. Accessed from the engine bay, 2 were blind and recessed. Apart from that it was straight forward. Worth bagging and labelling screws as you go. Take pictures to help reassembly.

Bought a front heater matrix from www.adrad.co.uk just over

I've found the answer to my question..... a Youtube video clip showing a VW Passat heater box being removed clearly showed that there is no coolant flow valve. The heater matrix has water flowing through it regardless of hot/cold control. Heat is regulated solely by air flow flaps and blower motor. Need to source a front heater matrix. Best price I've seen for a new one is

- please delete, duplicate

Vehicle Sharan 1997 1.9 TDI without air con. The front heater has developed a leak. Screen mists up immediately if heater turned on. The front carpets are dry but moisture is felt underneath heater ducts. I know this is a big job and involves removing the complete facia, steering column etc... I will attempt this before autumn. Before ordering a replacement heater matrix I need to know a few points regarding the control of coolent flow. Is the matrix sealed with just a flow and return pipe ? How is the water flow controlled as it may be the control valve leaking instead of the matrix. I'm unable to get any clear diagrams to show these details.

I assume you are refering to the booster heater. VCDS will not communicate with booster heater on Mk1. As far as I am aware, any fault codes logged will erase when ignition is turned off. To diagnose faults you will need to test with a multi meter at the connector block. Most failures are the glow plug. The diesel dosing pump can fail, terminals corrode.

Update.... unbolted the booster heater for more testing. Correct voltages seen on multiplug terminals 1 and 6 and earth ok on pin 2. Retested components on the multiplug going in to heater, all looking good. Only thing not looked at was the 12 volt diesel metering pump. Sure enough, open circuit on pins 3 and 4. I checked the pump and found both spade terminals had become detached due to corrosion. Removed the pump, cleaned it up and managed to solder wires to the remains of the spade terninals. After satisfying myself that the joints were mechanicaly sound and conducting ok with no leakage to the pump body, I encased the terminals first in epoxy resin finished of with chemical metal and then a lick of hammerite paint. Stuck it back on the car ready for test. Bridged the Thermo sensor terminals and started the car. The familier sound of the jet engine and time bomb tick (from the pump) was music to my ears. The car is 15 years old with 166K on the clock and this has been the first time the Booster heater has failed. I first assumed it was glow plug failure even though it tested ok. I removed it for inspection and was surprised to find it looking like new ! The best bit is that the repair didn't cost a penny... not counting my time of course. See pics of the repaired pump :

The correct filter for the AHU engine is Mann W840/2 or equivalent.

Right... fuse 14 is ok, also serves reversing lights and electric sun roof. Re-tested at Thermo contacts and seeing battery voltage. Very odd... couldn't have been getting a good contact with my test probs yesterday. Not happy, would have been nice an easy. Anyway, bridged the contacts with engine running.... no activity on the booster. The fuse box is numbered 1 to 22. Relays are above and further up are the auxillery fuses un numbered. Just one rated at 30 amps which I assume is Fuse 23 and that's ok. Only thing to do now is to unbolt the booster heater again for further investigation checking both voltage feeds via f14 and f23. Should appear at the Booster connector pins 1 and 6 and take it from there..... will have to wait for a nice dry/ warm day unlike today !! . I suppose the sealed ecu within the Booster can fail... I'll find out and update the post.. not sure when though ! Thanks for your help Chris.

That's great, much appreciated..... everything else working ok but will do further checking and testing tomorrow... updates to follow.

Thanks.... I also checked the owners handbook which lists the fuses including additional fuses above the relays, none of which mention aux/ booster heater. I'll do the 12 volt test Sunday and update the post...

Sharan MK 1 early 1997. Done some more digging around and found a D3W Z Erberspacher wiring diagram. You are right, the thermo switch should have 12 volts which should be presented to pin 6 on the multi plug at the heater. Tomorrow I'll do a test and stick a 12 volt supply to one side of the thermo switch connector. My next question is why no 12 volts... The Ford TIS Galaxy wiring diagram show fuse 14 feeding the thermo switch. Different on the Sharan. I checked all the fuses that I could see but all look ok. There must be a fues hiding somewhere ! Battery terminal wires all intact and corrosion free.

Ok, I know there is a lot of info on the booster heater but nothing covers my issue. My MK 1 Sharan TDI has the D3W Z Erberspacher unit. According to sources from this forum, the booster heater resets itself after the ignition is switched off, unlike the later MK 2. Therefore any lock outs clear themselves. My heater will not fire up at all. I unbolted the heater and tested from the pin outs using the test procedure from the Ford TIS. Blower motor, glowplug, flame monitoring sensor and overheating sensor all test ok using a multimeter. I unplugged the outside temperature sensor mounted on the wiper linkage support and bridged the contacts, started the engine, after a few minutes- nothing. I believe the blower should kick in after about 40 seconds. I believe the contacts for the outside temperature sensor are the main switch for the booster and should have 12 volts on one side. I get about 2 volts. Can anyone verify this. I tested with engine running, One lead of multimeter connected to earth, the positive lead to one side of the contact. Has anyone got a wiring diagram for the Sharan MK1. I have the Haines book for the Galaxy but the wiring/ fuses differ.

For a transpoder key to be accepted by the vehicle immobiliser it must have a matching code. In my case the transponder chip in my key stopped transmitting. The cheap way round this is to buy a new transponder chip, get it programmed with the same code as the spare key. As the spare key code is logged on the vehicle immobiliser you can make as many duplicates as you like. Known as 'Clonning' . The expensive method is to buy a new key from Dealer. Their key comes with a code already programmed. Dealer then inputs the code on to the immobiliser. They charge

Key problem now resolved. After a bit of digging on the net found out the correct transponder type for my year. Cost inc delivery