ExitWound

I've done the searching and reading and think I have the circuit down as such.

DS = Driver's Side
PS = Passenger's Side
-------------------------
(1)DS wire-->(2)DS Shock-->(3)DS Grid Connector-->(4)Grid-->(5)PS Grid Connector -->(6)PS Shock-->(7)PS Shock ball connector-->(8)car body

If I set up the multimeter to measure the voltage across the circuit, I should read ~12V up through points 1, 2, and 3, correct? As the current passes through the grid, the readings should fall to zero as the grid acts as a giant resistor.

Currently, I'm reading 12V all the way through point 6, the passenger side connector where the grid connects to it. I see ZERO current through the strut itself, down to the ball. But I am seeing current at the PS side of the grid which I'm interpreting as a failure, which is why my defrosters won't work.

I purchased the new struts a while ago, making sure of the two part numbers and types of struts. The DS strut has a plastic ball connector, the PS strut has the trunk light switch and a metal ball connector. I can't figure out how the current passes through the strut, though, to the ball & socket joint. Here's a picture of the removed strut.



The ring connector sees current from the grid, however, there seems to be no connection possible down through the strut. It looks to be plastic but I could be wrong. The head screws on clamping down on the strut holding the ring/connector in place. Am I just missing something? Is the top of the strut metal? If not, how does the strut pass the current through to the ball socket?

I've cleaned most of the excess grease off the connections too. The default amount was a lot.

:confused in PA with more ice coming:

I hate the winter.

marky522

You said you are seeing current? Do you mean you are seeing voltage? The reason you are seeing 12v on the ground side of the circuit is because as you have found, the circuit doesnt have a ground, and a resistor only works with current flowing, in an open circuit there is no current flow so you dont get the voltage drop across the grid, so you see full voltage to the point of the open in the circuit. I would run a test lead from point 5 to ground, which should allow your defrost to start working. It looks to me like you just need to clean the paint off the bottom of that PS lift shock so that the ring can make a clean contact with the strut body.

HTH.

Mark

ExitWound

Helped a lot. Thanks!

I scraped off the end of the strut and put it back together. I'm now seeing 9.54V on the DS grid connector and .36V on the PS grid connector. Should I be seeing more than 9V? I can't notice if the grid is getting warm or not because the previous owner stuck on some window tinting (poor job, btw). I think I can feel the DS grid connector getting warm, but it could just be in my head.

DarylJ

You're in State College, so it's plenty cold enough to breathe on the window and fog it up. If the grid is on, you'll know.

ExitWound

HA! That's a good test actually. I'm feeling stupid for not thinking that.

marky522

Glad it worked out for ya! to tell you if you have current flowing take your mulitmeter and put it on both leads of the defrost, you should have nearly 12v! That is the voltage drop across the grid, and as you already learned an open will have no voltage drop, and a operating circtuit should have full voltage drop.

Mark

ExitWound

It's really astounding. I could integrate triple integrals, but I couldn't grasp basic electromagnetism. I took that class 2 times before giving it up. I've never been able to wrap my mind around it. I'm trying though, ten years later!

Question remains though: Why am I seeing 9V at the entry point on the grid instead of the 11.4 the rest of the circuits see? Is it possible I have some resistance somewhere prior to the grid? As I've read, there are numerous instances regarding the wire from the relay to the grid being wet, or corroded, or cut. Is 9V enough or should I continue looking?

marky522

9V should be fine, that indicates that you have resistance elsewhere in the circuit. The total circuit voltage is divided between the resistances. If you are concerned, grab a diagramof the circuit and find out where the wire that your testing origonates from and check you voltage there, .5v voltage drop is the accepted limit per wire.

Funny you make the comment about math, I can do cars all day long, Aced tech school, but cant do Trig to save my life...

Mark

DarylJ

Basic electromagnetism and breathing on your window to see if the defroster works isn't covered in "fancy book learnin'".

The only think I learned in school that helps me in every day life is that to really win, you have to be the one taking the checks. Also, I learned that there are lots of lazy cheating scumbags in the world that do in fact graduate, so I consider paper from any college to be useless when I'm hiring.

Oh...wait...I'm ranting off topic now.