Buzzing sound comming from under dash after glow plug replacment...

[linx310]

I tried to do a search on this issue, found a few post mentioning, but no real solutions and I wasn't even sure if they were talking about the same thing so I decided to film it.

Ok last week I replaced my glow plugs with AC Delco units (I think the 60g) and my wait light now stays on longer, the volt meter stays in the yellow for about 1 min and then I have a buzzing sound coming from under the dash and when it stops the voltmeter then goes to green.


The truck runs fine and starts great though, I am just wondering if this is normal.


I have recorded 3 videos displaying the concern. The temp outside was about 60 degrees.



Video 1: Video shows what the volt meter is doing and the buzzing sound can be heard.


[media]http://www.youtube.com/watch?v=ZciyhuNa_Ys[/media]

Video 2: I connected a volt meter to the top post of the glow plug relay to read the voltage. One lead was connected to ground, the other (bright red wire as seen in photo) was connected to the top post of the relay. In the video you can see the voltage steadily increase until buzzing sound is heard and it then cuts out.


[media]http://www.youtube.com/watch?v=hAlFF1-Lsco[/media]

Video 3: I repeated the same test, but connected the volt meter to a glow plug. Basically voltage slowly increased until buzzing sound is heard.

[media]http://www.youtube.com/watch?v=ZuEU8nEnP3I[/media]

Now I know the Glow Plugs are supposed to stay on for a bit after it starts, what has me worried is the buzzing sound.

 

[Warthog]

Is the buzzing coming from under the dash or on the firewall?

I don't have sound at work so your video isn't helpful.

 

[linx310]

It sounds like it coming from under the dash.

 

[antennaclimber]

Sounds like relay chatter from the GP relay.

Try cleaning all the connections on the GP relay, remove the GP card and clean the card edge connections. Visually check the solder connections (on the GP card) near the large transistor that is riveted to the board. Make sure they are intact and are not intermittant. Reflow them is they look questionable.
Karl

 

[linx310]

Confirmed it is the glow plug relay buzzing. It was so loud I thought it was coming from under the dash. Checked the Glow Plug card and it looks fine. Will try and clean glow plug relay contacts this weekend. I am wondering if I need a new relay.

 

[linx310]

BTW what actually makes a relay chatter like this?

 

[1stSarge]

Low battery voltage.
Loose/dirty/corroded connections.
And another, I touched on in this thread:

http://www.steelsoldiers.com/cucv/62606-86-6-2-glow-plug-module-repair-3.html

Look at post #26

 

[Speedzilla]

Bumping this thread seeking some help, I am having the exact same issue (Seems like it isn't charging, or has heavy draw, then vibration/chatter from the GP relay and the voltage comes up). The link above is no good anymore, bad relay or card?