Broken connection to the temperature sender gauge

toyota
pickup

#1

The lug of my temperature sender gauge, the part that mounts on the engine, has broken off. I can’t figure out how it connected. The factory service manual does not mention it. I can’t find it at the usual auto parts stores. It’s a long trip to a dealer. Has anyone suggestions?



Toyota Pickup '87, carbureted


#2

If you need to replace the sensor you should be able to order it on-line from someone and have it delivered to you.


#3

I suppose I could, but only the connection is broken: I’d prefer to fix it. How does the lug connect to the body?

Does this gauge do anything other than send a signal to the temperature receiver gauge on the dashboard? My pickup has no computer and it has a mechanical thermostat. Does anything else not work because this is disconnected?


#4

You are correct, on that vehicle it only sends a signal to the gage. But that gage could save your engine should you develop a cooling system problem, so you want to fix it.

I never had to change one on my Toyota pickups, but perhaps a call to the dealer’s repair department could yield the information you seek. They can look up the part on their computer and describe its mounting to you. My guess is that you’re alluding to the wire itself, and that’ll likely have had a terminal lug screwed to a post. The post probably broke off, and that will necessitate replacing the entire unit.

Here’s an idea: loook the replacement part up on the internet and see what looks different from yours.


#5

I definitely want to fix it, but if it controls the temperature of the engine/coolant I want not to drive until I fix it. From what I read about cars with computers they use the signal the coolant sender gauge emits to control the temperature of the engine: that’s crucial. But I have never had a problem with this truck overheating so I can wait a bit, even drive it if I check the coolant every time I stop.

I never looked at this until I replaced my fuel pump recently; the fuel pump blocks the view. Since the temperature gauge has always worked until now I must have broken it when
I took the fuel pump off.

The dealer’s repair department in town has never been useful to me yet.

I finally figured out the right name (‘coolant sender gauge’) and can see a picture
of it at the AutoZone website (in-stock! $15).

The wire is okay: it’s still attached to the lug that’s supposed to be part of the coolant
sender gauge but broke off. The picture shows a post that’s not there. I probably broke it off.

I can’t budge it but I don’t have the right socket: the 11/16" is just a hair too large and
I lack a 17 mm or 21/32". I suspect it’s 17 mm. I’ll buy a 17 mm socket, take it off,
and see if I can figure out away to substitute for the post. It’s brass: perhaps a self-tapping brass machine screw will go. Perhaps it’s foolish to waste any more time on a $15 part. I’m foolish, with my time, at least; not with my money or safety (or others’). I like figuring things out.


#6

Why doesn’t that vehicle have a computer? Did someone modify it?

BTW, an 11/16 WILL fit a 17mm hex head. They are almost exactly the same size, the 11/16 being only 18 thousandths of an inch larger.


#7

Maybe, that part isn’t the coolant temperature sensor, after all. Does it look like this one?: http://www.autozone.com/autozone/catalog/parts/partsShelf.jsp?categoryDisplayName=Climate+Control&fromType=parts&fromString=search&parentId=52-0&currentPage=1&filterByKeyWord=temperature+sensor&isSearchByPartNumber=false&navValue=15200113&categoryNValue=15299999&fromWhere=&itemId=113-0&displayName=Coolant+Temperature+Sensor&searchText=temperature+sensor You’ll need to register your truck at the autozone.com site to see the information.
There is an engine computer. There is a “water temperature switch” on p/u with 4 wheel drive.
The autozone Web site has more good information on your truck. It’s free.


#8
 Quoth Bodybagger:  'Why doesn't that vehicle have a computer? Did someone modify it?'
 It's an '87: it has a computer only when I bring my laptop with me. 

  Quoth Bodybagger:  'BTW, an 11/16 WILL fit a 17mm hex head.'
   It's close, but it started slipping over the nut: it's brass: I can

shine them off if I try hard enough. I had to work to get it off. I found
a 17 mm combination wrench.


#9

Post the link to the autozone.com site for the “coolant sender gauge”. I didn’t see that name, when I was there.


#10
 Quoth Hellokit:  'Maybe, that part isn't the coolant temperature sensor, after all.'
 I'm not absolutely sure.  I have had a hard time figuring out what it is.  Different

manuals have different names. But I discovered that the temperature gauge on the dash now
stays at the bottom and the picture in the Haynes shows the coolant sender gauge in the
right location. It’s broken, which makes it harder to identify.

 Quoth Hellokit: 'Does it look like this one?'
 Now that I look at it, it doesn't.  What I have is a wire with a broken-off lug

still stuck into its connector and a clean brass surface to which it would seem to
have used to been connected.
It looks more like the temperature switch, which I can’t find mentioned in either
Chilton’s or Haynes. What does the temperature switch do?

 Quoth Hellokit: 'There is an engine computer.'
  ???  I can't find any mention of one in the factory service manual, Chilton's,

Haynes, or the AutoZone website.


#11

AutoZone calls it the ‘coolant temperature sensor’ : http://www.autozone.com/autozone/catalog/parts/partsShelf.jsp?categoryDisplayName=Climate+Control&fromType=parts&fromString=search&parentId=52-0&currentPage=1&filterByKeyWord=coolant+temperature+sensor&isSearchByPartNumber=false&navValue=15200113&categoryNValue=15299999&fromWhere=&itemId=113-0&displayName=Coolant+Temperature+Sensor&searchText=coolant+temperature+sensor

Every manual I have uses a different name.


#12

You might, actually, be looking at the oil pressure sender.
It makes it easier for most people to understand when we refer to the electronic control module as a “computer”; because, it computes.


#13

Quoth Hellokit: ‘You might, actually, be looking at the oil pressure sender.’

That looks similar, physically, except it appears to be steel rather than brass.
The AutoZone website tells me the oil pressure sender is under the oil filter;
the part in question is above the oil filter.

Quoth Hellokit: ‘It makes it easier for most people to understand when we refer to the electronic control module as a “computer”; because, it computes.’

Does it? I’m dubious.

The ‘coolant temperature sensor’ is mounted in the intake manifold, the 'temperature switch’
in the cylinder head. I can’t see the cylinder head from the outside, but I can see the
intake manifold: I think it’s not mounted on the intake manifold.

Unfortunately applying a 17 mm wrench to it merely ground brass off it without moving it.
Do I need a 21/32? 5/8 is too small. Any suggestions for what to do when I have removed
all the edges?


#14
 It turned out to be the 'temperature switch': the TS isn't a switch: it sends a signal

to the temperature gauge in the dashboard. AutoZone had it in stock for $10.

 The 'coolant temperature sensor', which sounded like a more appropriate name, sends

a signal to the electronic control module.


#15

The EFI version of this engine had two coolant sensors, A CTS for the EFI computer, and a gauge sender for the gauge on the dash. The carbureted version only has the gauge sender. The coolant sending units are located near the thermostat housing in the intake manifold. The oil pressure sender is located on the engine block right near the oil filter. This only triggers the oil pressure light on the dash if the oil pressure drops to 6 psi or less.