I have a 1990 F150, 5.0L 4x2 and have been able to get the engine codes via the free method of jumping the STI plug to the body and watching the Check Engine light when the key is turned on.

My question is, for the purposes of diagnostics, would I get any advantage by buying an OBD 1 code reader. I was looking at an Actron for $25 and from what I can tell it simply flashes a light on the unit, just like the Check Engine light does. My gut level instinct is not to get it, simply the purposes of just counting a blinking light in a different location.

I spend $25 dollars to watch a light on the reader flash instead of watching the Check Engine light flash - I still have to do the counting, and figure out the numbers. I can do that for free.

Am I wrong here...do those OBD 1 code readers show you the codes in a digital format? Do they serve some other useful purpose?

Any input or insight is appreciated.

 

It will allow you to do other testing that you may not be able to accomplish with your free method.
Testing a running engine, cylinder balance testing, wire and connector reliability testing operating all relays etc.
Your call.