Erratic Temp Gauge - Help Please
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Freshman User
Joined: May 2006
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Erratic Temp Gauge - Help Please
Hope to get some help. I have a 2000 Excursion 2WD with the 6.8L V10. Bought it brand new and now has 95K miles. Coolant system flushed every 30K. At the 90K service, I replaced the thermostat. 5k miles later, the temp gauge will be rock steady in the normal range and suddenly rise to the red (literally in about 2 sec) and them immediatley fall back to normal. Another mile down the, same thing happens. Here's the kicker - this only happens when the a/c is set to "MAX A/C" This does not happen in the normal a/c setting or if the a/c is off. I replaced the thermostat again -- no help. I replaced the $12 temp sending unit -- no help. Finally broke down and took it to the dealer. They want $886.66 to replace the entire gauge cluster!! Seems to me if the gauge itself was bad, it would fluctuate all the time. Need help - going on a 5K mile road trip in three weeks and would like to have this resolved by them.
BTW - the engine is not overheating, measured the coolant when the needle hits the red, but coolant is at normal operting temp. Suggestions? Thanks in advance!<!-- / message --><!-- no sigs except when logged in -->
BTW - the engine is not overheating, measured the coolant when the needle hits the red, but coolant is at normal operting temp. Suggestions? Thanks in advance!<!-- / message --><!-- no sigs except when logged in -->
Sit. Stay.
Joined: Oct 2001
Posts: 18,308
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From: Washington State
Because of what you said last, I wouldn't worry about it.
For less than $150 you could get a pillar gauge pod and put in a water temp and tranny temp gauge that really work. Then just pull the wire on that back of the stock cluster and superglue the needle to whatever position you like!
For less than $150 you could get a pillar gauge pod and put in a water temp and tranny temp gauge that really work. Then just pull the wire on that back of the stock cluster and superglue the needle to whatever position you like!
FTE Leadership Emeritus
Joined: Jul 2002
Posts: 42,561
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From: Long Island USA
I second the "real gauge" solution.
But why would it only do it in max a/c?
My EVTM is out in the garage. I'll try to take a look at it later today and see if there's any connection (pun intended) between the two.
But why would it only do it in max a/c?
My EVTM is out in the garage. I'll try to take a look at it later today and see if there's any connection (pun intended) between the two.
Logistics Pro
Joined: Jan 2002
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There is only one explanation I can think of
DC grounding to the instrument cluster is loose, or corroded and the max ac with high fan amp draw is sucking all the life out of the temp gage
I would be un-plug and plug back in every connector under the dash and behind the center console paying attention to all the "bolted" to metal ground points that I could find long before I spent $800 bucks to a Ford tech who is just guessing
DC grounding to the instrument cluster is loose, or corroded and the max ac with high fan amp draw is sucking all the life out of the temp gage
I would be un-plug and plug back in every connector under the dash and behind the center console paying attention to all the "bolted" to metal ground points that I could find long before I spent $800 bucks to a Ford tech who is just guessing
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Thanks for all the inputs. I'm going to check all the grounds as suggested. If I go with a seperate gauge and unplug the dash gauge, will this effect the computer should a real overtemp situation occur -- that is, will the computer still shut down 5 of the cylinders to act as air pumps for cooling? Not sure if the computer gets this info from the temp sending unit that feeds the gauge or from another source. For now, we'll just keep the a/c on normal.
If I decide to add a temp gauge, I would also like to add a tranny temp gauge. Does anyone know a good source for a 2 gauge pod for the pillar? Also recommendations on gauge brand and how to install them would be greatly appreciated.
BTW, at newfordparts.com I can order a brand new guage cluster for $273.53 I can replace it myself, so that is a far cry from the $886the dealer wants!!
If I decide to add a temp gauge, I would also like to add a tranny temp gauge. Does anyone know a good source for a 2 gauge pod for the pillar? Also recommendations on gauge brand and how to install them would be greatly appreciated.
BTW, at newfordparts.com I can order a brand new guage cluster for $273.53 I can replace it myself, so that is a far cry from the $886the dealer wants!!
FTE Leadership Emeritus
Joined: Jul 2002
Posts: 42,561
Likes: 421
From: Long Island USA
The "limp mode" is triggered by the cylinder head temperature sensor.
Check out the discountfordparts guy here on FTE.
I forget his handle, but he's a sponsor, so he should be easy to find.
Check out the discountfordparts guy here on FTE.
I forget his handle, but he's a sponsor, so he should be easy to find.
Logistics Pro
Joined: Jan 2002
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I bet you save the 200Bucks with a loose connector or ground
If you opt for as after market gage do NOT disconnect any thing on the instrument cluster..
That cluster is totally computer controlled..there are no discreet or analog components..
If you opt for as after market gage do NOT disconnect any thing on the instrument cluster..
That cluster is totally computer controlled..there are no discreet or analog components..
