Temperature gauge stopped working

Dealing with all subsystems specific to the diesel powered Datsun-Nissan 720 pickup trucks.

Moderators:plenzen, Nissan_Ranger

Post Reply
EvergreenSD
Posts:70
Joined:14 years ago
Location:Eugene, OR
Temperature gauge stopped working

#1

Post by EvergreenSD » 13 years ago

Hi everybody,

This weekend I was under the hood tightening the water pump/alternator belt which made the chirping sound go away (yes the belt was loose, not worn out). When I was done I noticed that the temperature gauge is no longer working. I'm assuming that I bumped something while I was under there but I'm not sure where to start troubleshooting. There appear to be two sensors in the thermostat housing one with a single wire and one with two. I can't recall off hand which one is for the temperature gauge or what the other one does. I checked the wires for soundness and for dirty connections but I'm not sure what to do next. Is there a simple way to test that the sensor is working?

On an only slightly-related theoretical note, do you think that if a person were to overheat an SD22 without knowing that the oil pressure would drop enough that the DPC would save your ass before major damage occurred? I have not done this and wouldn't count it but this situation made me wonder if it would work like that. Thanks for the advice, you guys are the best.
'82 SD22 720 Kingcab with flatbed

User avatar
asavage
Site Admin
Posts:5351
Joined:15 years ago
Location:Duvall, Wash.
Contact:

Re: Temperature gauge stopped working

#2

Post by asavage » 13 years ago

EvergreenSD wrote:There appear to be two sensors in the thermostat housing one with a single wire and one with two.
Single wire is for the gauge.
Is there a simple way to test that the sensor is working?
Simple way takes TWO people.

One person inside, looks at temp gauge. Key ON. Other person under hood briefly -- and I mean briefly -- grounds the single wire. About one second. Do not ground it for longer than three seconds, or the gauge may be damaged.

When the single wire is grounded, the temp gauge's needle should begin rapidly swinging up toward 'H'. If not, look for wiring issues, gauge, or gauge voltage regulator (integrated into the instrument cluster).

Harder way is to use your FSM and an ohmmeter and test the resistance of the sender's terminal to ground, use the chart to ascertain what the resistance should be. They do not typically go bad on the Nissan. But the terminal collects corrosion, and the wire's terminal looses its spring tension. Philip has a post on this topic, if you use Search you may find it.
do you think that if a person were to overheat an SD22 without knowing, that the oil pressure would drop enough that the DPC would save your ass before major damage occurred?
No, I don't.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.

User avatar
philip
Posts:1494
Joined:15 years ago
Location:Southern California, USA

Re: Temperature gauge stopped working

#3

Post by philip » 13 years ago

EvergreenSD wrote:SNIP- There appear to be two sensors in the thermostat housing one with a single wire and one with two. I can't recall off hand which one is for the temperature gauge or what the other one does.


The single wire connects to your coolant temperature. That single female terminal must fit on FIRMLY ... not just the plastic tube around the terminal. Also make sure (about 6-8 inches away) another male/femal connector is secure

The twin conection is for your AutoGlow temperature.
evergreenSD wrote:On an only slightly-related theoretical note, do you think that if a person were to overheat an SD22 without knowing that the oil pressure would drop enough that the DPC would save your ass before major damage occurred?
It's possible if ... you had very thin engine oil, and/or very over heated oil (300°F), and idling low (ie 500 RPM). In that situation, oil pressure could drop under 10 psi which is the Oil Pressure Switch point.
-Philip
Passed 08May2008
My friend, you are missed . . .

1982 Datsun 720KC SD-22

"Im slow and I'm ahead of you"

EvergreenSD
Posts:70
Joined:14 years ago
Location:Eugene, OR

#4

Post by EvergreenSD » 13 years ago

Thnks so much for your help guys. It was just some corrosion on the connector between the sensor and the wire. I hadn't noticed that there was a connection in that spot. Your timely advice really helped me clear up this issue with a minimum of hassle. Much appreciated.
'82 SD22 720 Kingcab with flatbed

Post Reply

Who is online

Users browsing this forum: No registered users and 0 guests