Check engine light with a paper clip?

[mcdlnwright]

Hey guys me again,

I was at a parts house the other day and the guy was checking my check engine light. He was trying to use a machine but it was bad so he used a paper clip. I was wondering is that safe? and if so how can I do it. it would sure save me some time running to the auto store just to get it checked. I have a 1990 full size bronco. and my port is under the hood

[Truck]

I don't know about a paper clip, specifically. but you can use a volt-meter. The Haynes manual gives you the details about it. You plug in the neg/pos terminals in two of the slots, and wait for the needle to move. you count needle movements the same way you count the beeps on a code scanner. (one, two, three-pause-one, two, three) for a thirty-three.