Temp Gage Quit Working

[ford4wd08]

My '85 B2 temp gage quit working yesterday.

What are my options for replacement/troubleshooting?

I believe I can ground the wire on the and the gage should move to hot right?

My wiring looks pretty old, so I ordered a replacement wiring with the connector for the stud.

Can you replace the gage in the cluster if need be?

 

[franklin2]

In all the Fords I have ever had, I have never had a the gauge fail itself. You are correct, you can turn the key to run but do not start the engine, and then get someone to watch the gauge as you pull the wire off the sending unit and let it hang in the air, and then ground the wire. This should make the gauge swing back and forth.

Make sure you test the sending unit on top of the engine that has the single wire going to it. The computer for the engine used a sending unit/sensor that had two wires going to it.

If you do get a new sending unit, or are checking the old one, make sure it does not have gobs of sealing tape or sealer on the threads. A little dab of sealer on half the threads will help it seal, but you also need a good electrical ground connection through the threads to the engine metal.

 

[ford4wd08]

In all the Fords I have ever had, I have never had a the gauge fail itself. You are correct, you can turn the key to run but do not start the engine, and then get someone to watch the gauge as you pull the wire off the sending unit and let it hang in the air, and then ground the wire. This should make the gauge swing back and forth.

Make sure you test the sending unit on top of the engine that has the single wire going to it. The computer for the engine used a sending unit/sensor that had two wires going to it.

If you do get a new sending unit, or are checking the old one, make sure it does not have gobs of sealing tape or sealer on the threads. A little dab of sealer on half the threads will help it seal, but you also need a good electrical ground connection through the threads to the engine metal.

The 2 wire one is just a plug in a hole now lol. No wiring harness is going to it since the duraspark conversion.

I agree. I also ordered a new sending unit off rock auto since it was fairly cheap.

I'll play around with it more tonight. I suspect a short in the wiring to be honest.

 

[ford4wd08]

Replaced the sending unit and some of the bad wiring with a new connector, still doesn't work.... I'm afraid it might be the gage at the cluster, anyone know the steps for testing this?

Can these gages be repaired? I am guessing either the gage or the circuit board on the back has a short or something in it.

 

[franklin2]

Replaced the sending unit and some of the bad wiring with a new connector, still doesn't work.... I'm afraid it might be the gage at the cluster, anyone know the steps for testing this?

Can these gages be repaired? I am guessing either the gage or the circuit board on the back has a short or something in it.

Look at post #2 above, it has instructions for testing.

 

[ford4wd08]

Look at post #2 above, it has instructions for testing.

I got that, what are the next steps after than? Replace gage?

 

[franklin2]

I got that, what are the next steps after than? Replace gage?

If you got no movement with the key on and touching the sending unit wire to ground, I would then pull the cluster, find the same wire, and ground it at the plug with the key on and see if it moves. If you get nothing there, it would have to be a plug problem or a gauge problem, or possibly a circuit trace problem. I guess the gauge could go bad but it would be the first one I have ever heard of.

 

[ford4wd08]

Ended up being a bad connection at the back of the cluster... Got it fixed and now the B2 is running hot. Ha imagine that. I believe I need to clean out and flush the radiator very well. I'm going to try and get to that this weekend.

 

[RonD]

Before draining coolant check fan clutch
Cold engine before start up, spin the fan, should be tight, hard to turn, thats cold lock
Start engine, should hear the fan moving air because its locked, then in 5-10seconds noise should go away as clutch unlocks
Shut off engine, spin fan should spin easily

After driving when you get back home shut off engine and try spinning fan again, should be harder to spin, locked again because radiator is hot

If these things don't happen replace fan clutch

Pull out radiator after draining
Then flip it upside down(flip test), if ANY coolant comes out it has BLOCKED passages, replace it

You can lay it flat and fill with CLR mixed with HOT water, rad cap on
Let it sit for 15-20min then drain
Repeat as you see fit

Then Stand it up and put hand over lower rad hose port, fill it with water
Stop filling when full and remove hand, should drain instantly
Now do the Flip Test again, if water still comes out then cleaning won't fix it, replace it

 

[Uncle Gump]

Glad you got it fixed... we usually never see the correction... only the complaint.

I'm doing some clean up to keep the forum organized... so I'm putting this thread into the electrical and gauges forum.

 

[ford4wd08]

Before draining coolant check fan clutch
Cold engine before start up, spin the fan, should be tight, hard to turn, thats cold lock
Start engine, should hear the fan moving air because its locked, then in 5-10seconds noise should go away as clutch unlocks
Shut off engine, spin fan should spin easily

After driving when you get back home shut off engine and try spinning fan again, should be harder to spin, locked again because radiator is hot

If these things don't happen replace fan clutch

Pull out radiator after draining
Then flip it upside down(flip test), if ANY coolant comes out it has BLOCKED passages, replace it

You can lay it flat and fill with CLR mixed with HOT water, rad cap on
Let it sit for 15-20min then drain
Repeat as you see fit

Then Stand it up and put hand over lower rad hose port, fill it with water
Stop filling when full and remove hand, should drain instantly
Now do the Flip Test again, if water still comes out then cleaning won't fix it, replace it

Hi Ron, I actually just replaced the fan clutch last week.

I believe these are fluid filled and my old one had sticky residue all over it. Found one at a local AutoZone for $34 so decided to just go ahead and change it.

I believe it is a blockage in the radiator because of the way it overheats. If I start off in the morning and just drive it with no stop and go I have no issues.

If I hit any stop lights or stop and go for any amount of time, it will get to a certain point and the radiator can't keep up.

I actually had it get hot enough to boil the gas out of carb, but no boiling over of radiator once in a drive through.

That's where I'm at now anyhow. I know these gauges aren't the most accurate, but I fixed mine finally because of the overheat and it can get to H if I don't watch it.

 

[RonD]

With those symptoms it reads like fan clutch or water pump more than radiator, but could be

The engine generates more heat when under a load, driving, than at idle, so poor radiator flow tends to show up as temp going up when driving, radiator can't cool the 20deg needed so temp slowly goes up
Vehicles movement provides more air flow/cooling for radiator than any fan can

Temp going up when stopped usually means radiator air flow/cooling fan is not moving enough air thru it, and/or coolant circulation, i.e. water pump flow at low RPMs might not be optimum to move enough coolant thru radiator, but works fine above say 1,500rpm

It certainly could be the radiator, just pointing out some "classic" symptoms

And check the "new" fan clutch using above tests
New just means NEVER EVER TESTED, now-a-days, not "it works", lol
So grain of salt on any "new" parts

 

[franklin2]

If you are worried about it, go get a real gauge with numbers on it. My 84 Bronco II gauge reads on the upper part of the scale all the time. I put a real gauge on it and it's only running 200 degrees. When I climb the mountain I live on, it might get up to 210 or 220 on the hottest days. And that is with it wide open to the floor climbing the mountain. I still have the factory gauge hooked up too, and it's almost pegged in those situations, but the engine is fine.

You can waste a lot of money trusting the lousy factory gauges.

 

[ford4wd08]

With those symptoms it reads like fan clutch or water pump more than radiator, but could be

The engine generates more heat when under a load, driving, than at idle, so poor radiator flow tends to show up as temp going up when driving, radiator can't cool the 20deg needed so temp slowly goes up
Vehicles movement provides more air flow/cooling for radiator than any fan can

Temp going up when stopped usually means radiator air flow/cooling fan is not moving enough air thru it, and/or coolant circulation, i.e. water pump flow at low RPMs might not be optimum to move enough coolant thru radiator, but works fine above say 1,500rpm

It certainly could be the radiator, just pointing out some "classic" symptoms

And check the "new" fan clutch using above tests
New just means NEVER EVER TESTED, now-a-days, not "it works", lol
So grain of salt on any "new" parts

To me it seems like it can't dissipate the heat after driving then coming to a stop. Which seemed to be an airflow issue. If I am able to drive with the increased airflow, it seems to cool, but once it gets to a certain point, it can't keep up.

It is like it reaches a certain temperature then it can't recover.

I have thought about the water pump, which might be next on my list.

I know the coolant looks like crap, so a good flush and cleaning the radiator certainly won't hurt anything.

 

[ford4wd08]

If you are worried about it, go get a real gauge with numbers on it. My 84 Bronco II gauge reads on the upper part of the scale all the time. I put a real gauge on it and it's only running 200 degrees. When I climb the mountain I live on, it might get up to 210 or 220 on the hottest days. And that is with it wide open to the floor climbing the mountain. I still have the factory gauge hooked up too, and it's almost pegged in those situations, but the engine is fine.

You can waste a lot of money trusting the lousy factory gauges.

I wouldn't be as worried if it didn't die on me when I was driving and had to pull over to cool it off.

I know these gauges aren't the most accurate, but it used to run at the middle of the gage when at operating temp almost all the time, now it climbs up to the H too easily in my opinion.

I did save the original sender I replaced, I might actually install it again and see what it does.

Also, I have a infared camera on a fluke multimeter. I checked the temp with it idling in the driveway of the block when it was reading warm. It read 215 F, which isn't overheated by any means, but the engine wasn't being worked either, just idling.