• Mustang Forums
  • 1996 - 2004 SN95 Mustang -General/Talk-

Temp Gauges Not Working Properly. Please Help.

  • Thread starter Thread starter Saltlife850
  • Start date Start date Aug 9, 2017
S

Saltlife850

New Member
Aug 9, 2017
1
0
1
Aug 9, 2017
#1
  • Aug 9, 2017
  • #1
I just purchased a 2003 Mustang GT and I unfortunately didn't notice the Water Temp and Oil Temp gauges not fluctuating correctly. When I start the car and it's cold the gauges immediately go just passed middle and stay there, they don't fluctuate at all. The tach seems to work fine but the Speedo is off by about 15 mph aswell. It does have larger tires and a possible gear change so that would explain the Speedo error.
 

squeak93

15 Year Member
Jun 2, 2005
2,327
405
164
Joplin, Missouri
Aug 9, 2017
#2
  • Aug 9, 2017
  • #2
The oil is a pressure gauge and has a sensor down by the oil filter to replace. However, it should just go to the middle as it's more of a dummy gauge. It doesn't read actual pressure, just that there is X amount of pressure.

The water sensor is up on the rail by the t-stat, it could be bad as well. My water temp gauge "sticks" and moves if I tap on the plastic gauge shield on the dash. Other times it works perfect. My car had white face gauges added at some point from a previous owner so I'm guessing they jacked it up.
 

wmburns

SN Certified Technician
Aug 14, 2009
5,892
514
204
Houston Texas
Aug 9, 2017
#3
  • Aug 9, 2017
  • #3
+1 on the oil sender. The position of the needle means nothing regarding the amount of oil pressure. It's an analog idiot light. Either shows OK or not-OK.

For the 1999+ model year the dash temperature gauge displays what the PCM "tells" it to display. This is different from the 1998 and older where there's a separate sender just for the dash gauge. So if trying to trouble shoot this problem it's necessary to know what the PCM "thinks" the engine coolant temperature is (ECT).

If the ECT value is correct in the PCM and the dash gauge is not correct THEN the problem is in the cluster.

If the ECT value is not correct, then the problem is in the ECT sender, wiring, or system voltage (alternator/charging system).

There is a ground behind the center console that is shared with multiple devices including the cluster, GEM, and radio. It's frequently messes up during a radio install. Not a bad idea to confirm that the cluster wires black wires with white stripes have a low resistance back to battery negative.
 
You must log in or register to reply here.

Similar threads

J
'96 Cobra: A/C gets weak and engine misfires under load when warm
  • jruhnke
  • Oct 22, 2025
  • SVT Tech Forum
Replies
2
Views
395
SVT Tech Forum Nov 20, 2025
nickyb
SURGING IDLE / NO IDLE CHECKLIST FOR 1999–2004 MUSTANG GT (4.6L 2V) - Work In Progress
  • Noobz347
  • Aug 30, 2025
  • 1996 - 2004 SN95 Mustang -General/Talk-
Replies
0
Views
1K
1996 - 2004 SN95 Mustang -General/Talk- Aug 30, 2025
Noobz347
SURGING IDLE / NO IDLE CHECKLIST FOR 1996–1998 MUSTANG GT (4.6L 2V) - Work In Progress
  • Noobz347
  • Aug 30, 2025
  • 1996 - 2004 SN95 Mustang -General/Talk-
Replies
0
Views
932
1996 - 2004 SN95 Mustang -General/Talk- Aug 30, 2025
Noobz347
Electrical Innovate PSB-1 is DOA? Am I an idiot? All plausable. Please Help
  • Dontknowchit
  • Apr 26, 2025
  • Fox 5.0 Mustang Tech
Replies
1
Views
567
Fox 5.0 Mustang Tech Apr 26, 2025
Dontknowchit
L
Engine Need help diagnosing 2 dead cylinders
  • lvgnmz
  • Feb 13, 2025
  • Fox 5.0 Mustang Tech
Replies
3
Views
505
Fox 5.0 Mustang Tech Feb 13, 2025
Mustang5L5
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1996 - 2004 SN95 Mustang -General/Talk-
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?