im back... overheating... damn car..

[kaltenacht]

First off just wanted to say hey to all the old members on the board, I havent been on in a while but glad to be back. I am asking for pictures from other fellow members, with 86 or 87 LXIs. I am trying to locate my coolant temp sensor.... I think I have found the remains of my old one but, i cannot confirm it.. Haynes manuals hasnt helped neither does the online manual I downloaded... If anyone could take pictures of the area just behind their themostat housing. I need the area that has the sensor for the gauge, and the other sensor. Actually just to the side. The reason why I am asking is because I was trying to rewire my fans cause some other jackass just straight wired them to my power window fuse... And I found some sort of 'plug' just behind the thermostat housing a little to the left side. I took it out and it looks like the remains of some sort of sensor. SO any help would be great, ill try to get a picture, but i dont have a camera so i dunno for sure. Oh ya and I tried the search and came up with this

http://www.picvault.info/images/173831_Untitled-1.jpg

I am assuming the one that says new is the coolant temp sensor, but I cant really tell its location, which is why I am asking for pics. Anyway thanks for any help.

[kaltenacht]

no help?

[kaltenacht]

guess not..

[Bglad420]

Your coolant temp sensor is on the radiator, by the lower radiator hose

[chappymane]

I think, based on my own reasons to explore this topic, that u have located the two sensors one of which is ur temp sensor. u need some proffessional electrical schematics to tell u exactly which of the two to pinpoint as ur problem area. as I said i am pretty sure the temp sensor is located right where thst picture is.

[chappymane]

also u r probably not overheating sole based upon ur fans not coming on these cars really rarly need those fans if every thing else in ur cooling system is working properly. check for air in system or ur pump, which if not leaking or grinding terribly is undoughtably good. otherwise a bad thermostat may cause this issue. then fans in a hooter climate will cause this problem.

[kaltenacht]

Well, I went ahead and bought my temp switch, coolant temp sensor, and rad fan switch and replaced them. I figured i was going to have to sooner or later and 48 bucks for all three wasnt bad either. i had to do some rewiring, because when I went to unplug the temp switch from the connector the wire just fell out. So that might have been part of the problem lol. I also bought my sub cooling fan relay and still no luck. I've checked my wires and looked at some wiring diagrams, and Im pretty sure its going to be the main cooling fan relay (mitsuba rc-2203). I ran a few tests also to come to this conclusion. After I get this crap fixed I might write up a tutorial on troubleshooting your cooling system cause I've learned a SHIT LOAD from this. But anyway thanks for the help thus far.

[kaltenacht]

First off thank you 3geez for making me RETYPE this effin think again.... Let me see if I can REMEMBER everything I just freakin typed... KK, deep breath.....and release....

Problem: Cooling fan will not turn on. End result overheating...

I purchased coolant temp sensor, temp switch, and rad fan switch. Installed and checked/cleaned connections, still nothing. So I then purchased both the cooling fan relay and sub cooling fan relay. Installed and still nothing. Now instead of not thinking of the fan motor being burned out, I check it. Straight wire it to the battery, works perfect... Moving on. Next step to me would be to check for power going to the relays. I know the sub cooling fan relay works because I can jump the two terminals on the cooling fan relay and hear the sub cooling fan relay click on and off. The two terminals I jump are, according to the schematic printed on the relay, the two that run power to the coil in the relay. Terminals 1 and 2 to be exact. Meanwhile I check the power for the other two terminals on the cooling fan relay. Only one gets power. This would be the terminal, if looking at the schematic on the relay, closest to the top on the left. Which makes sense because only one of the two terminals are going to have power, that is until the switch is closed. So at this point in time you might be thinking about the fuse in the fuse box under the dash. Checked that to. Its getting power. How do I know this? Because if I pull it, the power review mirrors dont work. And if you look at the schematic the cooling fan fuse also runs the power review mirror circuit. So no power to the power review mirror circuit means no power to the cooling fan relay. And that means no power to the radaitor fan. So the only other thing I can now think of the a bad ground? But that would mean no power in the circuit period. Same with a break. And a short would mean only power half the time. Which everything has constant power when it should.

Also take a look at this picture...
http://www.picvault.info/images/173831_Untitled-1.jpg

According to the thread I found the green one is the temp switch... Well I replaced the temp switch, and that is the one that controls the instrument cluster temp gauge. The smaller one that says new accross it. The the black one is the coolant temperature sensor, I replaced that one also. So what would the green one be called. And what does it do? How many damn sensors do our cars really have? Three or four? Here is my list

Temp Switch (Wells part #TU75) Instrument Cluster Gauge
Coolant Temp Sensor (Wells part #SU410) ECU
Rad Fan Switch Controls Power to the Rad Fan Motor

Now looking at the black and green sensor, they look similar, so should I expect similar voltage reading from them? If so, would it make sense then to just use another coolant temp sensor to replace the green one?

What am i leaving out here? I've tried and tested everything I could think of. Can someone think of something else here? Or does anyone have a subscription to alldatadiy.com? That would be great! Any help would be great. Please!
:madflip: u car. :rant:

[kaltenacht]

bump

[shepherd79]

i think you should download the shop manual. Find the sticky in Technical section. It will explain.
I want to say they are the same except the size of threads, but since i don't have the shop manual in the front of me i won't say that.
just get the manual and look at it.

[kaltenacht]

i think you should download the shop manual. Find the sticky in Technical section. It will explain.
I want to say they are the same except the size of threads, but since i don't have the shop manual in the front of me i won't say that.
just get the manual and look at it.

I have looked at the shop manual, i downloaded it a while back. It only mentioned the Temp Switch and the Fan thermosensor (Rad Fan Switch). The Coolant Temp Sensor, and the other, I cannot find. What exactly does the green sensor do anyhow? By the way I dont think I mentioned this before but its a LXI not carbed.

[kaltenacht]

dont everyone jump at once now...

great...

[kaltenacht]

well, i couldnt figure out what to do next, so i decided just to wire the rad fan up to a toggle switch and mount it in my car... it works for now, atleast until i figure out what the real problem is. one thing is for sure though. this thread is DEAD

[Versanick]

I have both of my fans (cut the blue wire) hooked up on switches. I don't them on usually when the car's on. most of the time at least one's on, and when I run the motor hard, I make sure they're both on. Makes it cool to drive. switches and stuff.

if your temperature says it's too high, maybe your thermostat isn't opening. I'd get a 180 deg thermostat anyway. I was running too hot, and it fixed my problem. (I even blew a headgasket b/c it was too hot).. good luck with the sensor.

[kaltenacht]

I have both of my fans (cut the blue wire) hooked up on switches. I don't them on usually when the car's on. most of the time at least one's on, and when I run the motor hard, I make sure they're both on. Makes it cool to drive. switches and stuff.

if your temperature says it's too high, maybe your thermostat isn't opening. I'd get a 180 deg thermostat anyway. I was running too hot, and it fixed my problem. (I even blew a headgasket b/c it was too hot).. good luck with the sensor.

well it doesnt run hot, unless i dont turn the rad fan on... But i was wanting to get it running the RIGHT way.. I dont think its the thermostat, because it wouldnt cause the fans to not run would it? Anyway thanks for the reply.

[DBMaster]

OK, I know this one because I recently replaced the coolant temp (TW) sensor. That is the black one in your photo. It sends the temp signal to the ECU to control fuel mixture. The green one is a thermoswitch. It is the one that signals the ECU to turn the A/C condenser (smaller) fan on for 15 minutes after the engine is off if the coolant temp is above a certain temp. The small one marked "New" is for your temp gauge.

BTW, the temp sensor in the lower radiator tank turns both fans on and off when the engine is running.

[DBMaster]

By the way, how did you rewire your sensors? My wires were brittle and shot and broke off the plugs. My local Honda mechanic cut a couple off some old wiring harnesses he had in the shop and gave them to me. Can you actually buy new plugs somewhere?