v6 - 'Heat' warning lamp (disabling)

[pixies]

Hi all,

Have just purchased an old 1997 Bongo and the constant red 'Heat' warning lamp is really annoying. I guess the temp sensor has failed, as it recently passed the emission tests just fine.

I have seen people mention 'disabling' the warning lamp - is it just a case of disconnecting the sensor? Is this an under the van job, or can it be reached by lifting a seat?

I don't want to remove the bulb, as this lamp is used in conjunction with another lamp to indicate a failed scavenger fan.

ta
N

[windywatson]

The sensor is mounted on the side of the catalytic converter & can easily be seen from underneath. I assume that it switches the light on by its resistance becoming lower as the exhaust gets hotter. Therefore it would seem that it may have failed. I would first try removing the wire from the sensor to see if that puts out the light. If that doesn't work perhaps others may be able to help you with a resolution. The other option will be to remove the bulb from the back of the instrument cluster. It's not to difficult to remove & the bulbs remove easily.
The later vehicles don't have this warning light. It only exists to warn you how hot the CAT is so you don't park over flammable material such as long grass & start a fire.

[g8dhe]

The sensor is actually for Oxygen in the exhaust as I understand it, this signals back to the ECU to adjust the fuel injection level so that a better efficiency is obtained and also helps to reduce the emissions as its the surplus Oxygen combining with the Nitrogen that causes the Nitrous oxides (NOx) to be produced.
The "heat" indicator is used as the excess Oxygen causes the catalyst to overheat and burn out the catalyst as well as causing the bad emissions.
Blanking off the warning light will cost you money, cause pollution and possibly fail the MoT, your choice ......
See http://www.standardautoparts.com/need-r ... converter/ for more info, but many sites explaining the problem.

[windywatson]

I have 2 V6's the early one has the extra sensor on the side of the CAT & the later doesn't. If what you say is correct surely both vans would this, as your logic would apply in both cases. When I asked at the exhuast centre who were fitting a stainless sytem to me van how they would deal with the sensor situation as the replacement CAT dosen't have one. It was them that told me that it was just a warning system to let you know that the cat was hot enough to cause risk of fire if parking over flamable substances such as long dry grass. I have also read threads on here where members who are having new exhausts fitted. What to do with the wire that connects to the sensor on the side of the old CAT? The usual answer is to just leave it disconected.
However with respect to the original post, I have just checked the hand book that details the dash light warnings. This actually says that "this warning light will appear when there is a fault in the scavenging fan". So not sure now if Pixes heat warning lamp is not actually related to the scavenging fan. And nothing to do with the CAT.

Cheers

[g8dhe]

Your assuming that they have the same ECU, the ECU versions change at a quite considerable rate of knots, given the variations in codings on them! Several years back now I was talking with George of BongoSpares about some modules so that I could reverse engineer them, he kept on giving me more and more versions of ECU's despite the fact that I wasn't going to do the ECU's !!

As regards the Heat light it flashes if the scavenger fan is in operation or out of kilter, but stays on permanent to indicate overheating I believe.