HI there BC...
Been a really long time and I wish I could be here more often!!!!

I have been having a problem with my ECC

I f the car is in traffic or warming up (Its cold here right now!) the heat will come on initially- but after a few min- for some reason the car thinks that its hot outside and turns on the AC...Its very strange. The ext temp will begin to soar if the car is parked and idling or is in traffic.

I have tried changing the ext temp sensor- which did not make any difference as well as the ECC unit and nothing either.

Im really hopeing that someone can help me here- casue this is really anoying.

thank-you!!!!1

Something is heating up the ext temp sensor if it is spiking up while idling or there is a short in the wiring somewhere. Is it mounted correctly away from the radiator?
this really should be moved to electrical.

Sorry- I wasnt 100% sure where to post this.

I wondered if there was something to do with where its mounted also- but it is mounted on the piece of metal that the hood conects to the body- where the release is.

its very odd I know- and I wondered if it had somehting to do with the sensor itself- but Ive tried other ones with the ame problem :?

You have a short to ground somewhere in the circuit. A lower sensor resistance is a higher temperature.

If any of your temp sensors on the car have the signal wire short to ground or partially short through corrosion, the indicated temperature will climb. Carefully inspect your wiring harness for the ambient air temp. It'* in a very exposed location. Make sure it'* in a dry condition. Clean the contacts and seal it up with dielectric grease. Salt water conducts electricity and may be causing a partial short (unexpected high resistance to ground).

Welcome back. It'* been awhile.

Thanks for the info Bill!

I will take a look at that tonight.

Thanks for the weclome back too I really miss it here Just been so busy with my apprenticeship.

I will check the wiring and I think that I have some dielectric grease.

Well the temp dropped completly again...I attempted to inspect some of the wiring and looking for bad grounds. I didnt see anything that jumped out at me, which is a good thing.

However- I was looking in my service manual- and the ECC is capable of diagnosing its problems (yes thats right a 17 year old car can do this- yet another score for this car!)

So anyway- it flashes codes accross based on the codes that came up they are intermitient problems.

the codes that came up are as follows:

101 in vehicle temp short

103 ambient temp sensor short (what and where is the ambient temp sensor it does not show in the manual :?

104 ambient temp sensor open

If there was not a 1 in front of these codes- it would be a problem that was taking place right away. The 1 indicates that these are the problems that the computer has controlled.

as it is farrr too cold to try and fix this now- and since I do have heat (for now) Im going to hold of for a slightly warmer day- but I do need some imput as to what to do next.
Im hoping someone can help...Bill?! SSEbonne4eva?
thanks

Ambient temp is the external temp sensor. 101 seems to indicate a short has (had) been identified in the internal temp sensor as well. Not familiar at all (yet) with the 87-91 Bonne, so not exactly sure of the next steps, other than examining or replacing the external Temp sensor (which, you did and may be why the codes are stored). Is there anyway to "clear" the stored codes? If so, you may want to do that to see if they reoccur again. If they don't then you have no problem to fix. If they (or some) do return, then you know what is failing.

Echo- thatnks for clearing up the ambient temp sensor location. I picked up a spare one from the yard the other day- on Bills advice- I have not yet installed it.

I did clear the codes upon initial testing of this feature of stored info in the ECC. the ECC did fail once today- so there is definitly a problem- about 4 min later the heat came back on again.

I will try replacing the ambient temp sensor- and see if the other two codes pop up. as well as re-set the unit. Let me know if you find out anything else.

thanks very much

Highly unlikely you have a short in multiple circuits at the same time. Pull the hvac unit and remove the harness, clean up the connectors and any other associated parts. Apply dielectric grease and re test for codes.

I agree I think its odd that there would be so many shorts. Ill try the dielectric grease and cleaning everything- I hope that this works. Thanks for your imput !!