Heater sender Unit

[thor]

I am now assuming that this is the sender unit.

My water pump was leaking not too bad but it eventually got slightly worse, I was monitoring the thing then last week, started up in the morning out onto the road and within a very short time the heater gauge was up around 3/4 , I stopped checked everything, then started again after a little while the gauge dropped suddenly to the bottom then eventually climbed as normal....I assumed that this was the finish of my pump, so I booked it in. the following day at first start the temp gauge went up above 1/2 way, because I was doing a great deal of towing over the weekend, I left the truck with an obliging local garage [borrowing another truck from a mate] who replaced the pump.....I collected the vehicle low and behold the gauge shot above half for a short time then dropped after a little while.
Does this sound like the heater sender or a faulty thermostat or what??

Just been out vehicle not used all day.....I turned the key prior to engaging starter and for the first time I noticed that the heater gauge moved to 1/2way then after a short time of engine running it dropped to cold then moved up slowly. mmmm 8O

 

[iandouglas]

heater sender unit????????????

hi thor .
regarding your TEMP GAUGE . dropping ,falling ect.
sounds like you may have 2 or more problems going on.
FIRST thing i would try is LOOK AT THE SIDE OF THE THERMOSTAT HOUSING (where the top hose fits to engine) look for electrical push on connectors problebly 3 of them. all to do with water temp .
ONE will go to ecu
ONE will go to your "temp gauge"
ONE will go somewhere else to do with emmitions control (i think)
.......................
THE ONE YOU WANT is the temp gauge one .
depending on type of connector look for a metal (wire) clip screwdriver under it WATCH WHERE IT GOES CAUSE YOU CAN BET IT WILL FLY.
OFF.
CAREFULLY Pull connector of clean up contacts look for corrosion (clean it up )see if you can tweak the contacts up a bit if they are loose.
now try your ignition see if works .
IT SHOULD BE AT BOTTOM OF GAUGE WITH A COLD ENGINE ,START IT UP RUN IT TILL HEAT COMES THROUGH HEATER KEEP AN EYE ON GAUGE IT SHOULD CLIMB ,THEN DROP BACK ONCE THERMOSTAT OPENS.
WHEN ALL WORKING AGAIN AND YOU ARE HAPPY THEN CLEAN THE OTHERS UP ONE AT A TIME.
HOPE THIS HELPS.
rgds.iandouglas

 

[thor]

There appears to be only two units on the side of the thermostat housing, a small one to-wards the front and a larger one behind, I managed to pull off the smaller one and clean it, then was unable to pull off the larger one [with two wires] but the gauge appeared normal for a few days, then occasionally same thing happens at the first cold start......gauge rises to about centre, start engine run for a very short time and it drops 8O :lol:
I can live with it but I would still prefer to sort it.
I assume the larger connection should just pull off...cos I cannot see a clip. :roll:

 

[iandouglas]

heater sender unit????????????

GOOD MORNING THOR.
I think you may be on the right track .
does the small one appear to be tight on the connections ?
what sort of lock does that have on it?
the larger one will have a lock of some sort look for a sprung wire U shaped arrangement that is what is on mine .you leaver it away and plug then pulls off.
or it may be a plastic clip built as part of the plug .
press down or pull up sort of thing
...................
as regards gauge working normally for a few days ,it sounds as though
its a loose conection perhaps on the larger plug.
cauld you get someone to wiggle plug about while you watch the gauge ,to see if it makes the needle behave differantly.
DONT TRY TO FORCE THE LARGE PLUG OFF THERE WILL BE A LOCK .
UNLESS ITS MISSING
GO VERY CAREFULLY AND TRY TO DETERMIN IF ITS THE PLUG THAT IS HOLDING FAST OR THE CONTACTS CORRODED THUS HOLDING TOGETHER.

PLEASE DONT BREAK ANYTHING.
good luck rgds,iandouglas
ps .
perhaps someone else on here could have a look at there`s and see if they can spot the lock.