hood grounded

[Euphoric306]

i can't help but wonder why ford decided to go out of their way to make sure the hood is grounded..... really doesn't make any sense to me... for those running fiberglass hoods it doesn't mess up anything electrical, doesn't have to do with any magnetic or inductive fields for the plug wires... nothing is connected to the hood latch electrically....


anybody with any info on why this trivial engineering technique found its way onto the mustang?

 

[z2o_what]

are you talking about the strap towards the cowl or the wires for the light under the hood?

because i thought that the strap was just a way to tell if the hood had been removed

 

[Euphoric306]

well i was just checking out this picture i have on my computer of a 93 engine bay and it lists all the parts and a short description of each one. i saw hood ground strap and i started thinking my hood has that same thing... but my hood doesn't have the light under the hood so that didn't occur to me.

is that grounded through the hood or does it have it's own wires

 

[vristang]

I always assumed the strap was for the under hood light. Not sure how it works, but I think the under hood light turns on when that hood-strap connection is broken. The light should have 2 wires running to it.

I never looked real close at this system though.

I would like to hear the thoughts of others as well.

Good Question Euphoric306

jason

 

[HISSIN50]

When driving at speed, considerable friction from air passing over the hood is generated. This creates enough juice to allow serious shock to anyone touching the body. Grounding the hood helps diffuse/discharge this pent up static charge.



























Anyone buy that?

 

[91lxttrim]

uh... how do you touch the hood while you're driving?

 

[Saleen0679]

The only thing I've ever read about the hood ground:

Hood Ground - The hood ground is especially important if your antenna is mounted on the front fender, or in the windshield glass. Check the ground strap for the hood (this will be a small, curved piece of metal attached to the cowl that touches the hood when it is closed, grounding it to the firewall). You will want to make sure that it is still in place, and that it is still making good contact. If not, you will want to replace it.

 

[Dean85GT]

why? and what happens if you buy a new hood

 

[vristang]

Wow, there are alot of theories on this subject.

I can test mine by bending the ground strap down, and seeing if the light still functions properly.

Anyone out there have a composite hood?

jason

 

[Euphoric306]

vristang if your previous theory is correct, then the light will still light up when the hood is closed. try opening the hood and using a jumper cable to ground the hood tot he firewall when it's open. if the light turns off, then that would lead me to believe the function of the ground strap is to turn off the underhood light when the hood is closed.


the static electricity/friction theory i can't help but be amazed at anyone who would come up with that haha.

anyone with a fiberglass hood have any problems with radio reception?

 

[91lxttrim]

I have 4" cowl and I haven't noticed any difference in radio reception. I always thought that thing was there to help support the insulation under the hood. uh jk? lol?

I have no idea.

 

[SeventyMach1]

I have the strap connected to my Cervini's glass hood. I figure it might help hold the hood down in the case that it decides to fly off, lol.


I don't see how it would have ANYTHING to do with aiding the antenna for reception.


On the under hood light .... doesn't that thing have like mercury or something in it that makes it turn on and off by orientation?

 

[Saleen0679]

It doesn't have anything to to with reception, but with noise interference from the electrical/ignition systems.

From one site:
"The hood must be properly grounded to prevent the engine compartment from radiating noise to the antenna."

I think it is more of an engineering 'just in case'. Some cars come with a ground cable from the hood to the block, some don't come with any ground.

 

[Euphoric306]

makes sense saleen. you've got a lot of answers i've needed lately.

 

[HISSIN50]

you've got a lot of answers i've needed lately.

He really knows his stuff - definately a very valuable member here (especially with electrical circuits and issues).

 

[393Bird]

Saleen0679 is correct. It is for both ignition noise supression in the sound system, AND to help the antenna to provide a better ground plane. The antenna is a 1/4 wave for the desired frequency range, and the body provides the other half that is required. Without the hood being part of the grounded mass, the reception would not be as even from the front as the rear of the car from distant stations.