I have a 99 C5 with an abundance of problems, several of which are with the power seat. these are the most annoying to me since I have to deal with them on an almost daily basis. I'm trying to work through the problems which I think its going to result in replacing some expensive electronics in them. I have a service manual and I have been looking through it for solutions. in a nutshell, this is what the seat does:

periodically stops moving in any direction. I push the switch to move the seat, it will move, then sometimes just stop. I keep holding the switch, no movement. if I let go for a split second then push it again, it continues to move properly.

the memory feature is screwy, sometimes it moves to completely wrong locations. most of the time it tries to move correctly then stops, I think its the same problem as above.

the rear vertical adjustment doesn't work. the motor is moving because I can hear it, it even moves a certain amount of time and then stops as if something is moving and reaching the limit switches. but the seat does not move with it. the front up and down works fine.

the power side bolsters don't work, but they do make noise when I push the button.

I'm thinking the first two problems are going to require a replacement of the seat relay center, and the SCM. I want to try to swap some parts and try to diagnose this because when the service manual gets to the part about replacing parts, it gets expensive if it turns out to not be the problem!

sorry for the long post...but my question is: where is the seat relay center? I see it in the wiring diagrams but I can't find info on replacing it or where it is. could is possibly be part of the SCM? is there any way I could take the relay center out of the drivers seat and swap it with the one in the passenger's seat? both have the same power features except the driver's seat has memory on it also. the passengers seat works fine, if I could swap the relays that might go along way towards helping me fix this problem, I can find everything else in the manual except for that!

please help! thanks in advance.

 

sounds like the problem i had with mine , but mine ended up being one of the turn buckle adjustment rods broke , and was catching in the carpet and tore a hole in it and it would get hung up in it . i had to buy a seat track used and do some part swapping , search some of the used parts yards . i yhink i gaot mine from corvette salvage for like $250.00 gm wanted 850.00 for the rail . good luck

oak

 

I have that problem as well. I was told the weld on the rail split. I'm taking it to a buddy of mine who's a mechanic to take a closer look...

 

Well I found the problem with the rear up and down motion. as I suspected it was mechanical. sounds like you guys had the same problem. the rear turnbuckle thing is broken. why was that made out of plastic anyway? I also have a hole in my carpet. I still have half of it on there so I decided I would go the bandaid route for now. I put a bolt threw it with a few washers and a couple of nuts. something tells me its not going to work for too long that way, but hopefully it will work long enough for me to get it replaced. unfortunately that's one of the lower priority problems. any ideas on the intermittent failure to move?

by the way, what are these two things under here? they look like leather wrapped padded boxes, but they have wires coming out of them. I haven't found any reference to them in the manual one of them is attached loosely to the seat power frame with a black wire tie! almost looks out of place there.

edit - looks like they are the pumps for the lumbar support and side bolsters.

 

I had the exact same problem with my 99 vert. The back bottom adjuster stopped working. Could hear the motor. Since I had the common fore and aft seat movement problem I went ahead and ordered a new seat track from gene culley. $480!!!

The part that breaks is made out of a white plastic that obviously becomes embrittled with age. If you use the easy entry feature, the seat is pushed against the back of the carpet when it moves fully aft. This jams the seat and puts pressure on this plastic part. After I replaced the seat track I turned off the easy entry feature and simply set driver 3 to the full aft position.

It is ridiculous that this ocurrs. Another instance of GM cutting cost at the expense of their customer.
Rich Bailey

 

funny was wondering today what was up with my seat as well. got a 99 vert 3months ago and just noticed recently that one one my power seat buttons makes a noise but i dont feel anything move when i press it. was going to look in the manual to see what that button does? its not the lumbar or the side adj or the front and back movement so its what ever else?

 

Same here on my 99'. I agree with Parussky, GM cutting silly costs. However, I have a BMW, same plastic crap for the window regulater...

 

i have a set of rails and motors for sale