The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - Trying to find the vsb (vehicle speed buffer).

72timemachine · 07-02-2018, 04:05 PM

Hello,

I have a 1990 GMC c2500 2 wheel drive with a 350 engine and 400th transmission. Speedometer and odometer are operating intermittently. They have a tendency to work once the truck has been driven for several miles.

I did test the vss at the tail shaft of the trans with my meter set on a/c volts to see if I was getting a pulse signal from the reluctor ring and the vss, seems to be in range when the driveshaft was rotated. The wires and connecting plug to the vss appear to look in good condition and is clean at the connecting points.

My question is, where the heck is the vsb (vehicle speed buffer module) I have been reading about? This is perhaps one of the most misunderstood topics I have read about. Seems to be a lot of misinformation or no information about the location of where it is on my year truck.

There is nothing in my dash cluster, I do not see it, even with a mirror and flashlight, behind the dash cluster and in front on the a/c ducting. It is not located left of the ecm behind the glove box or fastened on the backside of the dash left of the glove box.

Thank you ahead of time if you happen to know where this thing is hiding, burning up the internet for what it looks like and where it is seems to be a dead end.

07-02-2018, 04:05 PM	#1
72timemachine Registered User Join Date: Oct 2008 Location: los angeles ca Posts: 210	Trying to find the vsb (vehicle speed buffer). Hello, I have a 1990 GMC c2500 2 wheel drive with a 350 engine and 400th transmission. Speedometer and odometer are operating intermittently. They have a tendency to work once the truck has been driven for several miles. I did test the vss at the tail shaft of the trans with my meter set on a/c volts to see if I was getting a pulse signal from the reluctor ring and the vss, seems to be in range when the driveshaft was rotated. The wires and connecting plug to the vss appear to look in good condition and is clean at the connecting points. My question is, where the heck is the vsb (vehicle speed buffer module) I have been reading about? This is perhaps one of the most misunderstood topics I have read about. Seems to be a lot of misinformation or no information about the location of where it is on my year truck. There is nothing in my dash cluster, I do not see it, even with a mirror and flashlight, behind the dash cluster and in front on the a/c ducting. It is not located left of the ecm behind the glove box or fastened on the backside of the dash left of the glove box. Thank you ahead of time if you happen to know where this thing is hiding, burning up the internet for what it looks like and where it is seems to be a dead end.