Temp Gauge Not Working Properly

[shonkers 6]

Hi guys my temp gauge goes straight to max when i turn on ignition then goes back to minimum and doesnt move, ive had a look under dizzy and blue plug and black plug above sad unit cleane d them upand put them back but gauge still doing it. While i was there i saw two sensors one long one short with no wires to them and i cant find are they defunct and could this be my problem. Its an 88 1.6 with a 1.9 in it much appreciated if anyone can throw some light on this

[Kane 34]

Sounds to me you've got your coolant temp sensor and coolant temp switch wired the wrong way round.

[shonkers 6]

I cant have theres no wires on them, and the blue and black one are idiot proofso you cant get them mixed up

[welshpug 1,666]

sounds like the wires are earthing if you see movement, obviously the two sender and switch do need to be connected for the dash to work

 

an 88 car IIRC will have a brown multiplug in the engine bay near the afm/starter motor area, earlier cars will have a smaller one, 3 or 4 wires, later will have a 7 wire plug, later still don't have one at all, it would be a wise move to renew the wires from the senders past where the plug would be fitted into good clean wire in the engine loom, doing away with the plug.

[dobboy 231 2 Cars]

My 88 had a little brown plug under/behind dizzy, three wire job spliting into three separate wires serving coolant, oil, and sump.

[shonkers 6]

Yes there is a 3wire brown multi plug under afm which go to blue plug sensor under dizzy and black plug sensor under the sad but there are no wires going to the long and short sensors at the back of the t stat

[welshpug 1,666]

so put some in then!

[shonkers 6]

Ok where do i put them in, am i right in thinking from sensor to multiplug under dash

[dobboy 231 2 Cars]

Shonkers, think I have you a bum steer. My three wires went 2 for water, 1 for oil.

 

Post a pic of what you've got before you do anything drastic.

[shonkers 6]

Ok ill try

[dobboy 231 2 Cars]

if you can't manage to upload a pic, i've found a pic of mines showing the coolant sensors..... but ive used all my server space on here and cant post any pics on here.

 

It's easy.... three pin plug, one wire out to short coolant sensor (gauge iirc), one wire to adjacent sensor (long iirc), one wire down the back to oil sump (usually insulation on this wire is brittle).

 

Easy to fathom the wires too..... just get someone to flash them to earth one at a time whilst you watch the dash and see what moves.

[shonkers 6]

Something weird going on.i cant find the 3 wire plug maybe mine is the later one and doesnt have one at all.The only one leads to blue plug under dizzy ill have another root and see what i come up with. Ive found a 7 pin brown multiplug by fusebox and it has a light blue wire with 47a on it which is the temp gauge wire.

[shonkers 6]

heres an update, ive found a 3wire brown plug nestling above gearbox, the 3 wires no 47, no 47a and a white one go to loom and the other way is 1 thicker grey wire going into gearbox that looks like a flywheel sensor, so what do you reckon that is then

[dobboy 231 2 Cars]

Shonkers, the 47's are familiar. I post a photo for you of how mines was later so you know what to look for (hopefully).

[dobboy 231 2 Cars]

shomkers, drop me a PM with your email address and i'll send you a couple of pics that might help.

[dobboy 231 2 Cars]

BTW, i've just checked, the 47's are the wires for your coolant sensors for sure.

[TaffyTim 6]

Both wires are for the coolant, coolant temp gauge wire 47a, the warning light wire 47. They need to go to the wireless sensors you've mentioned.

[shonkers 6]

Ive just thought it might be to do with engine swap i replaced the 1.6 with. 1.9

[dobboy 231 2 Cars]

here's a few pics that i have that might help

 

 

 

[dobboy 231 2 Cars]

Not sure they pics will help. The yellow and white wires meet a wire coming up the back of the engine from the oil temp? sensor (which has a sleeve on it or is thicker (can't remember)...... these three wires the joint into a 3 pin plug. (the oil sensor is one of the end wires)

 

If you've found the 3-pin plu on the loom then it's easy to work out what goes where, if you need any help just say.

Edited September 26, 2014 by dobboy

[shonkers 6]

Hi thanks for pics not much help im afraid the 3 wires from multiplug go to loom which in turn go to dash and the other end 3 wires go down back of engine into gearbox that looks like a flywheel senksor im baffled

[welshpug 1,666]

sounds like someone plugged the wrong plug in, look for another 3 pin plug.

[dobboy 231 2 Cars]

Get the air pipes off and battery out and start hunting for them, they'll be there somewhere. What year is the car?

[shonkers 6]

Thats a thought but i coudnt find one when i took afm battery etc off a few weeks ago ill do it again an see what turns up thanks for advice