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> Breakouts > uActivate Circuit Test Assistant

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Universal Relay Adapter Cable

uActivate Circuit Test Assistant

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The new uActivate is now available to those on the Wait-list.

  • Wait-list customers will receive an email invitation in staggered groups, beginning with those who have been waiting the longest.
  • The invitation email includes instructions for logging into the uActivate site which will enable the ability to make a purchase of only one kit (at this time) and or multiple accessories.
  • If you are on the waiting list and have not received an invitation yet, you will.
  • If you are not on the waiting list, click here to be added.

Learn more about the new uActivate.


The original uActivate...

What makes the uActivate so amazing?
With only one connection to the circuit you can do a multitude of circuit tests. Think of it as the ultimate circuit breakout box!

What does the uActivate do?
With your DMM or lab scope, and an amp probe, you can perform voltage, current, and resistance tests via one physical connection to the circuit. In other words, it makes it easy to do full electrical performance testing of a circuit.

How does the uActivate connect to the circuit?
The uActivate connects in series to the circuit via the:  • Relay socket  • Fuse  • Connector

Will the uActivate activate the circuit or the relay?
It activates the circuit! First connect to the circuit by removing the relay and connecting the uActivate into the relay socket. Second, flip the switch on the front panel of the uActivate to activate the circuit.  Monitor the control signal of the relay by watching the LED located above the switch on the uActivate front panel.

It does not test relays. Jorge from says, “If you have to replace a relay it is important to also test the circuit. Sometimes, testing a relay is best done by testing the circuit - if the circuit is good then perhaps the relay is bad.

How does the uActivate connnect to a DMM or Lab Scope?
With one connection to the circuit, the uActivate lets you can obtain voltage and current measurements.

For voltage measurements, insert your DMM or lab scope test leads into the test ports:
- Banana Sockets (on top panel) access circuit wires that connect to relay contact (30 and 87).
- Pin Sockets (on front panel) access the relay coil – relay control wires (85 and 86).

For current measurements, clamp an amp probe around the 'current loop' located at the bottom of the uActivate. The 'current loop' is in series with the switch

What do the LEDs indicate?
The uActivate has two bi-colored LEDs. Each LED will shine either red or green depending on the polarity of the circuit. The color of the LED indicates which test port as the more positive side of the circuit. 
- LED above the switch: references the main circuit polarity (87/30).
- LED below the switch: references the relay control polarity (85/86).
Most relay circuits designate the power side of the circuit as terminal “30” and the load side as “87”. With the uActivate you don't need to worry about that. The bi-color LEDs indicate which test port is connected to the power side of the circuit, and the other test port for the load side of the circuit. This can be helpful when performing voltage verse resistance tests.

Does the uActivate perform any tests?
No. Like a breakout box, the uActivate provides a convenient connection to the circuit for your test equipment without affecting circuit performance.  But, the LEDs on the uActivate do indicate the state of the circuit:
- LED above the switch indicates the power (30) to the load (87).
- LED below the switch indicates power to the (85) and (86) control of a relay when connected via a relay socket.

• uActivate base unit
• Mini ISO Relay Adapter (commonly used on Bosch, Ford, GM)
• Micro 280 Relay Adapter (commonly used on GM)
• Micro Relay Adapter (commonly used on Ford, Toyota, Honda, etc.)
• Universal Relay Adapter Cable
• Terminal Leads for use with Universal Relay Adapter Cable. 
• Plastic Case



Voltage drop on the load side

In this scenario the next step is to check the integrity of the circuit between the relay contacts and the ground. This is a little more difficult doing a voltage test to check for excessive resistances.


First, activate the circuit and note the voltage via the uActivate (on the load side of the switch).


Next, find a test point as close to the load as possible. Activate the circuit and compare voltage measurements.


A lower voltage at the second test point indicates a resistance problem in the circuit between the relay contact (first test point) and the second test point. "


Resistance Test

The uActivate makes it easy to perform the resistance test.


Make sure the uActivate contact switch is open. Connect your DMM to a known good system ground, and put the test probe into the load side of the uActivate. This measures the resistance of the circuit between the "load side" relay contact, the load and the ground. If resistance is excessive, you know where to look, just follow the wires!


What do you do when you can not access a test point close to the load such as in the case of fuel pump?


Many circuits do not have published specs for current. However, many publish specs for resistance.


Current Test

Often, a voltage test offers very little information as to the general performance of a circuit. On the other hand, a current test shows how the circuit is using the energy giving a good indication of circuit work and performance.


Consider a typical switch to power circuit: The test point for a voltage test is between the load and the switch. When the circuit switches on, the voltage reads source voltage. There is often no indication of circuit work. The only indication is the intent to energize the circuit.


Why do simultaneous current and voltage tests?

The voltage test qualifies the current test. This is especially important for circuits with electrical motors.


Consider this: A resistance problem within a circuit can result in an unwanted change of current. The problem is that a minor change in current can be very difficult to detect. Especially if there are no ""good"" specs to compare to. On the other hand, a voltage drop test is very accurate. Via the uActivate test ports you can perform a voltage drop test of the circuit between the relay contacts and the power source. When the circuit is activated using the uActivate, any changes in voltage via the test port will be the result of the power sources inability to supply the adequate current or a voltage drop due to excessive resistance between the test point and the power source.











Ford EEC-IV No Start No Fuel Pressure Troubleshooting (Lincoln Towncar) with ScannerDanner

Paul puts down his test light (incredible!) and spends lots of time with the uActivate. Go to timestamp 7:55 to see why.




No Start, Engine Cranks Okay, Troubleshooting With Basic Tools (No Power to Injectors) with ScannerDanner

Paul tests spark, fuel pressure and injector pulse and the engine main relay for proper operation. The vehicle is a 2005 Chevy Equinox with a 3.4L engine. Is it a relay?




Diagnosing The Cause Of An A/C Compressor That Won't Turn On - The Trainer, with Pete Meier

A compressor clutch that won't engage can be caused by a lot of different issues, from a low refrigerant level to a blown fuse. Learn methods for quickly determining what the cause of the concern is in this edition of "The Trainer".





Part 1: ScannerDanner uses the uActivate to "jump the starter" and activate the Fuel Pump

At timestamp 19:00 minutes Paul concludes scan data analysis and moves into the shop to do fuel pressure tests.  Watch as he flips the switch on the uActivate to bypass the relay and crank the engine to watch fuel pressure.


After pinching off a return line at timestamp 30:50, Paul uses the uActivate on the fuel pump to rule out a stuck open regulator. He then uses the 'amp loop' on the uActivate to measure fuel pump current with his VantagePro.





Part 2: ScannerDanner uses the uActivate to after installing a new fuel pump




ScannerDanner goes mobile on a No Start Ford, with a camera on his head

Out of the classroom and into the snow to earn some money as a mobile tech. With a camera on his head, Paul records his thought process from start to finish as he diagnoses this Ford no start. He uses an old Snap-on Vantage (Heritage) and the AES uActivate.


ScannerDanner relearns how to use the uActivate on a No Start

How to slow down a profitable job? Forget how the tool operates. 



Pete Meier of Motor Age gives his impressions of the AES uActivate. Source:





1996 GMC Suburban Fuel pump analysis and repair

Performing a state of health check on this 330K mile ‘96 GMC Suburban 7.4L revealed fuel pressure within specification. However, the system suffers from low rest pressure. 

Jump into the service bay with Scott Brown at Connie & Dick’s Auto Service Center in Claremont CA, as he performs a few quick checks in order to evaluate the vehicle’s fuel delivery system against its original engineering design.

Extra points to notice in the presentation:
• Workspace and workstation setup
• Tool selection and application
• Component location look up
• Electrical circuit health
• Pump speed

 Tools used:
- AES uActivate
- Fuel Flow Meter similar to the MityVac 5545.
- PicoScope 



Troubleshooting a No Start, No Spark, No Fuel, No Com (any car)

2006 Lincoln LS, ScannerDanner walks us through a no start, no com using the 5 volt reference circuit as a guide.  He discusses voltage drop testing, why a loaded circuit is important and the standard relay testing that everyone needs to know. These testing procedures are not car specific.  This video starts at timestamp 30:26 when he starts using the uActivate with his old Vantage.


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