MGL Vega TC-4 Thermocouple EGT / CHT Indicator

Add to Wishlist
Part# 11-15994
MFR Model# TC-4


The TC-4 for Experimental / LSA aircraft is a 2 1/4" Sunlight readable 4 channel thermocouple color display instrument.

Instrument can be configured for 5 different temperature display screens. The display can be configured to group EGTs and CHTs to common settings or each thermocouple channel can be independently displayed with individual programmable high alarm and probe type. The TC-4 also has a trend graph and maximum values display screen.

The TC-4s high accuracy is due to its built in thermocouple linearization curves and cold junction compensation techniques. Temperature probes can be common J, K or E type thermocouple probes as used in CHT and EGT senders. Temperatures can be displayed in degrees Celsius or degrees Fahrenheit from -100C to 1200C (-148F to 2192F).

The TC-4 also features a built in engine leaning facility which allows the pilot to optimize the fuel mixture according to peak EGT temperatures as well as a cruise mode facility to provide instant identification of changing EGT/CHT trends.

The TC-4 can also be interfaced via the CAN bus to an external RDAC unit (Remote Data Acquisition Unit). This allows for easier installation as the RDAC unit is normally mounted in the engine compartment.
California Prop 65 Warning Symbol

WARNING: Cancer and Reproductive Harm -


  • 5 different temperature display screens
  • Supports J, K and E type thermocouple probes
  • Temperatures can be displayed in C or F from -100C to 1200C (-148F to 2192F)
  • High accuracy: Built in thermocouple linearization curves and cold junction compensation
  • Records maximum temperatures reached for each channel
  • Includes a trend graph display of each thermocouple channel
  • Engine leaning function according to peak EGT temperatures
  • Engine cruise mode to instantly identify changing EGT/CHT trends
  • External RDAC interfacing via the CAN bus
  • An external output activates when a high alarm condition has been reached
  • Frequently Purchased With
  • Customers Also Viewed
  • Related Items


Very nice little instrument for the money. Despite its small size, the readout is very easy to see.

William F Verified Purchase


December 27, 2023

Installed this instrument into my RV-9. All four cylinders were connected to the instrument with bayonet probes. It installed in minutes in a, now, unused locaction. I connected the wiring and the probes, turned it on and it fired right up indicating the current OAT. Used the manual to set it up for my desired displays and it was very easy. Im considering getting another for my EGTs.

Robert M
August 5, 2018

Installed fine, but does not operate as expected. Useful if you only want to see 4 temperatures total from your engine - even with the RDAC. The manual states clearly up front Up to 12 Thermocouples can be measured using the external RDAC. Yes, there is only 4 channels displayed at a time. However there is no way to cycle between those other channels simply with the rotary knob - say 4 EGT and 4 CHT sensors. To choose which 4 channels are displayed on the screen you navigate into a settings menu with several clicks. Further, you can only choose one set of bar graph labels and corresponding alarm temperatures - vs setting labels and and temp limits for each group of four channels. Why the manual advertises accepting up to 12 thermocouples with the RDAC is lost on me. Im contacting MGL in case Im mis-understanding this units function. If I am, I will update this review. I think its great hardware and MGL has a great lineup, just very confused on why the software doesnt let you rotary knob between groups of 4 with corresponding labels and temp limits. The point of adding an engine monitor vs cheap single cylinder analog gauage is to see all CHT and EGTs.

Brent D
October 25, 2023


Please note,'s personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician. assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.

Q: Does this come with four CHT thermocouples? If not, which do you recommend for my Jabiru engine?

No, you will have to purchase CHT probes separately, please view see # 11-05562

Q: What type of plug attaches to the rear of this MGL Vega TC-4 unit? Or do the Thermocouplers attach directly to the rear?

The thermocouplers attach to the unit via a DB9 male connector.

Q: Does this come with four EGT thermocouples?

Per the Manufacturer: No, you will need to purchase the EGT probes separately.

Q: How is the connection made to the db9? Are the T/C leads soldered to the db9 Pins?

A harness is provided for this unit to help with the installation, however these are crimp style connectors

Q: Could this instrument be used with a water temperature sender in order to use two EGT senders, one CHT and one water temperature?

It is recommended to use the probes suggested in the installation manual. Please review the document found in the Documents section of the webpage.