Heat Sensor problem 2.0

[bcowie]

so are u guys say if you remove the ac system that it will stop the fan from working? cause ive been trying to get mine to work for ever.

not the rad fan only the condenser fan.

there is a diode between the AC and rad fan so if the ac goes on so does the rad fan but not vice versa

[Mazda_Powered]

I had my 2 ground clips reversed and my coolant gauge works now, as well as my fan.

[1st Gen]

I'm sorry I can't really comment with any certainty about any of your questions. I'm just figuring this out for myself. I hate giving people direction and having it turn out to be wrong. The best I can do is maybe offer some methods for problem solving. People have said harness problems are a hassle to find, lol, maybe some known testing procedures would help in that isolation process. "This is what worked for me" is the best I can hope to achieve.

I was going to run a wire from the sensor to the plug yesterday just to see what would happen. This was just a jumper with some alligator clips. As it turned out, I was completely wrong about which plug on the back of the cluster was the one for the sensor. I thought it was the one closest too the sensor but it turned out to be the black on in the middle. At least the black plug is the one that gives me the neg gauge response. I tested, as best as I was able at the time, the wire that i would have thought was the correct color code but got no feedback. That means I'm a bit stuck until I can get some quiet time to just fart around with it.

My helper is very good at some things but when it comes to quiet contemplation and reflection, eh. Maybe I need to work on my skills of misdirection before I can move on.

[1st Gen]

I got the harness out and on the floor of the living room. A visual inspection showed nothing of real consequence.

I swapped out the VAF plug and put a 4 wire TPS plug on this 4WD harness. I believe I also swapped out the 10 pin under dash plug.

I have no idea where the problem may be so I'm going to start with the mods I did.

http://www.feoa.net/modules.php?name...er=asc&start=0 The howto I followed for the TPS conversion

http://www.wihandyman.com/forum/showthread.php?49178-VAF-plug-comparisons&p=641805#post641805

http://www.wihandyman.com/forum/showthread.php?21859-GTX-WIRING-HARNESS-complete-HOW-TO&highlight=GTX%20plugs%20harness

This harness is missing the 2G pin out, (y/b) wire for the distributor. The other LX harness have this. The car runs so I'm not sure whether this is essential.

After pouring over my worklog to freshen up on the info, I realized that this car didn't come with a tach cluster. lol. Hrmm.

[1st Gen]

Something went horribly wrong. A little white smoke came wafting out from behind the right side of the gauge cluster at the same time the sun went behind a cloud. Now, no gauge lights, no start. If you see Kay, tell her she's a fickle bitch!

I realized the heat switch and the heat sensor are not the same thing. Ran a wire from the sensor to the gauge and got love. Spent time trying to track down the wire on the chassis plug but aside from unplugging and plugging back in, no changes were made.

WTB, dynamite, and lot's of it.

[1st Gen]

On the plus side, I've gotten a lot better at reading the wire diagrams.

[KAinjection]

Well this may be a little late but, on the BP there should be 3 plugs running to where your thermostat is located. The first one your holding in your hand in that picture is the gauge temp wire, and it has nothing to do with a the cooling fan or the computer, only the coolant gauge in the cluster. Also that wire looks exactly like on my escort and it would be BK/O although it appears brown. There is another single wire connector that is a coolant temp switch for the cooling fan relay. When the coolant reaches approx 200 degrees this switch grounds and activates the relay. Last you have a 2 wire plug and that one is your coolant temp sensor used by the ECU. Hope that helps

[1st Gen]

Back on track. The big blue ground wire wasn't seated properly and came unplugged. (oops) It seems to be working now. Back to trying to jumper the sensor.
The reason the lights went out on the cluster is because it burnt a trace. My thoughts are that once the main ground came loose, the second choice for all that current wasn't even close to being up to the task. That was my best gauge cluster too. At least I didn't fry the ECU or something equally tragic.

[bcowie]

You can jump the trace with a wire, what is the current situation?

[1st Gen]

I was going to run a separate wire for the gauge sensor so that I can get that problem fixed. I have a back up cluster so the trace getting burnt isn't too big a hang up. The back up is scaly though so fixing the other one is preferred. I have a pretty good understanding of the circuit now. I just wanted to get the exhaust done.

I haven't worked on this for a few weeks but will try here in a few days. I'll be sure to post back with any updates.