electrical problem DB7

[pete kimpton]

can anybody help, i have a 1997 DB7 3.2, when i put on the blower for the heater/cooling the temp gauge instantly moves into the red, the car isn't over heating the pointer just goes into the red, when i turn the blower off bingo the pointer instantly returns to normal running temp. I'm baffled !!!!!!!!!!!

[altawashm]

hmmmmm

[Boxer]

Crossed wire?

[solardone]

Hmmm that sounds horrible! did it just start one day or was it after work has been carried out or another fault had occurred?My best pointer for now is that the fans and heater dont cut in till sensing (LHS of matrix) water temp greater than 50deg c but that is still a different sensor to the main engine one but there may be a link.Give us some more clues!

[pete kimpton]

thanks for your reply solardone, well there's not much more i can tell you but the other day i noticed that when i put the lights on the same thing happened i.e. temperature gauge pointer rose to just below the red when i turned them off the pointer went back to normal pointing around the 12 O'clock mark. I spoke to an AM specialist who was also baffled by it, the only thing he thought it could be is a bad earth, any ideas will be more than welcome.
Thanks.

[solardone]

Does it happen to oil pressure gauge as well? if so take the engine earth strap off (lower left i think ) clean it and vasaline the connecting points.Possible contacts? Roys auto electrics in shepperton (cant find his number) he sorted early db7s when the dealers could not, or a Jag xjs specialist as most is the same as late celebration models.Keep the clues coming-does it happen if you switch on other high load items,heated screen perhaps?

[pete kimpton]

Cheers solardone, i'll do some investigations and get back to ya one thing i did notice the other day whether it's connected to the problem i don't know but when i took the face off the stereo it was very hot. Not Nice, is there a chance that when the after market stereo was fitted the wiring could of been dusturbed or maybe damaged ? as i said before i spoke to an AM specialist who was also baffled but did not see it as a major problem, he said he could understand if the temp gauge read lower i.e. power drain when other electrical operated systems in use.

Thanks

[pete kimpton]

Hi Solardone, the problem doesn't seem to be affecting the oil pressure gauge but i have found that when put on any any high load electrical system i.e. heating/cooling blower, (the higher speed i put it on the more the temp gauge needle rises) head lights (not side lights) rear window heater, these all have the same affect on the temp gauge needle. I'm well bloody confused.

[solardone]

Hi Pete,hmmm I am confused that the oil pressure is not affected but still think the first stage is to look at the engine earth,I have 2 db7s at home at the moment I will check them at the w/e and let you know location etc.Also I will try to see Roy the autoelectrician and pick his brains!

[pete kimpton]

Thanks Solardone much appreciated, i will get to the bottom of this problem if it kills me i bet it's something really stupid, I HOPE.

[solardone]

I spoke to Roy,He reckoned look for voltage stabiliser-I could not find one on the wiring diagram(that does not mean there is not one!).The temp sensor however has feed and return unlike older cars which used the engine earth as return.So I would suggest buying a Jag equiv temp sender ,which should not be more than £6 and plug it in,no need to install it into the block as a trial.If it doesnt make any difference you have lost £6,If it reads ok get the correct part from AM fit it in the block,happy days

[pete kimpton]

cheers solardone i'm off on me hols and the Aston is going in storage so i'll have a look when i get back lets hope it's the answer to my woes.

[Mckenzie500]

Originally Posted by pete kimpton

can anybody help, i have a 1997 DB7 3.2, when i put on the blower for the heater/cooling the temp gauge instantly moves into the red, the car isn't over heating the pointer just goes into the red, when i turn the blower off bingo the pointer instantly returns to normal running temp. I'm baffled !!!!!!!!!!!

The main problem with this car, is it runs fine on road, but sometimes it won't start up only...sometimes, even you get to hear the pump prime and runs out of fuel.

[Gil9713]

Pete,
If I may give my view as someone who had the same fault. It turned out to be a simple temperature sensor on the i6 3.2. Get your garage to renew it and bingo!
Good Luck
Gil

[pete kimpton]

Cheers Gil, i'll give that a try and fingers crossed it will sort out my on going problem.

Well Gil i have been looking on the Net for the heat sensor but it seems that there is more than one, so excuse my ignorance but could you give me a bit more info on what sensor i am looking for.


Many Thanks.

[Gil9713]

Just digging out the paperwork and will provide you with a part number.......get back ASAP
Gil

[pete kimpton]

Thanks Gil,
hope it solves the problem be nice to get it sorted once and for all.