2008 Buick Lucerne Fuel Pump Relay

[92sub]

As a general rule you should always probe connector terminals using the proper 'mating' connector terminal. This is how you ensure you don't CREATE a poor connection.
Sticking a round peg in a square hole didn't work when we were two......it doesn't work now either.

Glad to hear no problems so far!

 

[Cardiomac]

Re: [SOLVED]Re: 2008 Buick Lucerne Fuel Pump Relay

I own a 2008 Lucerne and have the EXACT same problem as Century61. Exact same burnout of the fuse block at the exact same location. Car wouldn't start and I was lucky to find the problem myself without paying a lot of money. Replaced the relay and it works for now while I'm waiting for a new fuse block. I ordered an OEM one from the big auction site for $19.95, far less that the $300 the dealer wanted.

Here is what I think is going on. The original relay coil gets hot normally or gets hotter than normal because of an internal coil short. In the original relay design, the coil housing is part of the switch circuit and basically pin 30 is a continuation of the coil housing. Thus the heat of the coil is transferred preferentially to pin 30 because of the way the relay is designed. This heat causes a loss of temper in the connector in the fuse block which leads to a poor connection and more heat. The loss of connection may be exacerbated by plastic insulation which melts inside the relay and flows down the pin. Eventually, the connection is lost and the car won't start. I think Buick is aware of this because the new relay I bought from them has been redesigned so that there is no longer thermal continuity between the coli housing and pin 30, and the coil housing is no longer part of the switch circuit. Also, the new relay coil ohms out at 145 ohms vs. 90 ohms for the old relay. The coil wiring on the new coil is finer than than it was on the old coil so I think this is a design change to cause the coil to run cooler, rather than just indicative that the old coil was shorted. Moreover, if you take the cover off the relay and run the engine, you find that the coil housing is the first thing to get hot, not the switch. So, again, I think the design of the original relay was flawed because it allowed this heat to be transmitted freely to the connector in the fuse block.

Fixing the problem requires replacing both the relay and the block because the connector in the block has been irreparably damaged by the defective relay.

 

[Cardiomac]

Duplicate reply.

 

[aljms]

Hello and thanks to everyone that posted on this issue. I have finally gotten to the bottom of it!

Recap: The fuel pump relay would heat up to such an extent that it would basically melt/burn. This prevented the car from starting as it controls the fuel pump.

My Mechanic (Cobbs Automotive, Osceola indiana) worked very hard on this issue and found a few things that were not right.

1. The fusebox next to the battery in the back seat was heavily corroded underneath for some reason. He removed it and had to clean it and re-terminate a bunch of wires.

2. The main ground cable for the car was not making good contact. He had to remove it from the body and clean the body contact areas and reinstall it.

3. The fuel pump was drawing 12 volts and he replaced it with another and now it only draws about 7 volts. My thought is that the fuel pump was damaged somehow from the other problems.

He spent alot of time on the car and I really feel for him. I know what its like since Im in the service field for computer systems. He also gave me a really big break on the labor. Kept the cost at just over 700 bucks.

The car runs great now. But I did ask him if he felt that the dealer I bought it from in Warsaw, Indiana had tried to cover up the problem instead of fixing it and in his opinion "yes". But that is all opinion.

So, I dont know if I can go back to the Dealer and complain and get them to pay some/all of the cost of repair as it was just over their 30 day deal by about 2 weeks or so. So, Im probably stuck with the bill. But Im sure they were less than honest with me. My mechanic said that it looked previously worked on in that area.

I have to say, I tried to do all my research very diligently but there are just some things you cannot discover until after you own it. The price you pay for a used car I guess.

As for the battery in the back seat deal, Its different but Im sure I will get used to it. I think it would look funny though if I had to give someone a jump or receive one 🙂.

I like the car. Its the nicest I have ever owned. It handles and feels like real luxury! However, I dont think Ill ever discover what all the buttons do!😀.

Thanks everyone for your comments once again.

Hi...im new on here n I am very much in need of finding a solution for my car. I am now experiencing my relay heating up n melting. What do I do? How do I fix it? I need help. Im on foot. Can someone walk me through step by step on the easiest solution. Please. Thanks

 

[century61]

Hi...im new on here n I am very much in need of finding a solution for my car. I am now experiencing my relay heating up n melting. What do I do? How do I fix it? I need help. Im on foot. Can someone walk me through step by step on the easiest solution. Please. Thanks

Im sorry to hear that your Buick is broke 🙁

To my understanding and from my experience is that when your relay heats up and starts to melt it also damages the cheaply made fuse box. You might be a candidate for a fuse box replacement. I have a great mechanic here in Indiana and he was able to find a used fusebox and replace it. That solved my problems.

Basically what happened in my case (and maybe yours) is that somewhere along the line from the first owner of the car to the dealership the 20 amp fuse was replaced by a 30amp fuse. This caused the relay to heat up and fail. However, This also damaged the fusebox among other things.

century61

 

[ivaf100]

I'm having the same problem with my 2008 Lucerne CXL. The fuel pump has been replaced and I just noticed the relay socket is burned so I'm planning on replacing the fuse block and the relay.

 

[Shandra]

So ivaf100 what happened after you replaced everything did it work

 

[pyro57]

Hey cardiomac. new here and really would like to know where you found the new box and how you verified it was a "better" one than the one GM put in at the factory. See your PM. Thanks. pyro57

- - - Updated - - -

I own a 2008 Lucerne and have the EXACT same problem as Century61. Exact same burnout of the fuse block at the exact same location. Car wouldn't start and I was lucky to find the problem myself without paying a lot of money. Replaced the relay and it works for now while I'm waiting for a new fuse block. I ordered an OEM one from the big auction site for $19.95, far less that the $300 the dealer wanted.

Here is what I think is going on. The original relay coil gets hot normally or gets hotter than normal because of an internal coil short. In the original relay design, the coil housing is part of the switch circuit and basically pin 30 is a continuation of the coil housing. Thus the heat of the coil is transferred preferentially to pin 30 because of the way the relay is designed. This heat causes a loss of temper in the connector in the fuse block which leads to a poor connection and more heat. The loss of connection may be exacerbated by plastic insulation which melts inside the relay and flows down the pin. Eventually, the connection is lost and the car won't start. I think Buick is aware of this because the new relay I bought from them has been redesigned so that there is no longer thermal continuity between the coli housing and pin 30, and the coil housing is no longer part of the switch circuit. Also, the new relay coil ohms out at 145 ohms vs. 90 ohms for the old relay. The coil wiring on the new coil is finer than than it was on the old coil so I think this is a design change to cause the coil to run cooler, rather than just indicative that the old coil was shorted. Moreover, if you take the cover off the relay and run the engine, you find that the coil housing is the first thing to get hot, not the switch. So, again, I think the design of the original relay was flawed because it allowed this heat to be transmitted freely to the connector in the fuse block.

Fixing the problem requires replacing both the relay and the block because the connector in the block has been irreparably damaged by the defective relay.

see your PM's please- pyro57

 

[RayenTiger]

I have a 2008 same problem. The fuel relay blew twice in 2 months. Does anyone know for sure if its the fuel pump or the fuse box? The amps on the fuel pump come back at about 8.5 amps. I tested another 3800 V6 its fuel pump was only using 6.2 amps. Has anyone tested the amps on their fuel pump to see what it reads? I don't want to buy a $400 fuel pump and later find that it wasn't the fuel pump at all but the fuse block or something else. Any help would be appreciated! Thank you

 

[squiretom]

i look forward that after replacing 3 door handles , and a motor mount , i might expect a problem with a fuse block under the back seat , assuming i can open the rear doors at the time the fuel pump relay melts the block. if the battery is to be kept cooler than the engine bay, would it be logical that no air flow under an insulating foam and leather seat might keep the relay heat from dissipating ?
i'm sure the bean counters were building up a reserve fund to pay for the recalls by using lowest cost foreign suppliers. with my recall for the ignition switch pending .......

 

[Jerrymick]

During recent out of state trip, engine turned over but failed to start. Traced problem to burned and discolored fuel pump relay and burned and melted female contact in rear under seat fuse box/relay panel. To continue trip home, I replaced fuel pump relay with aftermarket part.
As plastic can burn, I feel this should be an NHTSA issue!

 

[TooFly]

Re: [SOLVED]Re: 2008 Buick Lucerne Fuel Pump Relay

I'm having the same exact problems 2010 v8 lucerne anyone had results contacting Buick?

 

[TooFly]

Please report to safercar.gov

 

[century61]

Re: [SOLVED]Re: 2008 Buick Lucerne Fuel Pump Relay

I'm having the same exact problems 2010 v8 lucerne anyone had results contacting Buick?

My 2008 v6 Buick Lucerne takes a 20amp fuse for the fuel pump relay. Dealership put in a 30amp to just get it sold and off the lot.

My thinking is, Is that if your relay looks burnt or overly heated your probably going to have to actually replace the fuse box. The fuse box is made of cheap plastic and is not serviceable. The relay heats up and melts the plastic and the wire they use in the fuse box will arc over to other stuff and cause problems.

Now, Even though the 30amp fuse probably caused alot of this for me, Its not too far of a stretch for you to run into the same problem after a few cycles of 'overheating' on the fuel pump relay.

I ended up replacing the fuel pump, The fusebox (from junk yard), and the fuse (20amp) for the relay.

Im sorry to hear that you are having this issue. I am not a fan of GM anymore sad to say.

...

 

[jkmerchants]

This is actually a big problem known to GM. My 2010 Cadillac DTS is currently having the same issue. The fuse block it the exact match to Buick Lucerne and burns out in exact location.

My DTS have 30,000 miles, long story short relay fuse burns hot melting the block. My back seat has never been removed as I am original owner. So I removed it to investigate cause before I took car to dealer and discovered the ground cable to battery was corroded not on car frame but battery itself, also relay fuse burned. I bought a new relay fuse at local store installed, burned in 10 min. Called local dealer to get fuse block part number and was quoted 300 for block including install but refused to give me correct part numb. I searched eBay and found part for 80. Seller is currently selling 6-7 blocks daily with over 600 sold. The block is very easy to install, after disconnecting the battery simply remove positive, unclamp block from housing, and unscrew the three bolts in back of block, after unscrewing them you will need to pry the wire housing out with a screwdriver then unplug the two main wires. 20 min job, 10 to reinstall. Ok I replaced the block yet relay fuse still run hot enough that it could melt again. I ordered a neg cable and will change out once arrive to rule out ground issues. I'm not sure why the ground cable became lose enough to corrode but this had to come from factory. The bolt system on battery isn't the best. GM really need to bolt these down correctly at factory cause average person isn't going to remove the back seat unless theses a reason. This relay fuse issue needs to be recalled and corrected. Maybe they should inform customers to check their battery connections or change the faulty fuse blocks. Many people are spending trying to find a problem. Lots are spending hours online trying to find solutions. There's also reports of blocks burning up again within a year of being replaced.

 

[century61]

This is actually a big problem known to GM. My 2010 Cadillac DTS is currently having the same issue. The fuse block it the exact match to Buick Lucerne and burns out in exact location.

My DTS have 30,000 miles, long story short relay fuse burns hot melting the block. My back seat has never been removed as I am original owner. So I removed it to investigate cause before I took car to dealer and discovered the ground cable to battery was corroded not on car frame but battery itself, also relay fuse burned. I bought a new relay fuse at local store installed, burned in 10 min. Called local dealer to get fuse block part number and was quoted 300 for block including install but refused to give me correct part numb. I searched eBay and found part for 80. Seller is currently selling 6-7 blocks daily with over 600 sold. The block is very easy to install, after disconnecting the battery simply remove positive, unclamp block from housing, and unscrew the three bolts in back of block, after unscrewing them you will need to pry the wire housing out with a screwdriver then unplug the two main wires. 20 min job, 10 to reinstall. Ok I replaced the block yet relay fuse still run hot enough that it could melt again. I ordered a neg cable and will change out once arrive to rule out ground issues. I'm not sure why the ground cable became lose enough to corrode but this had to come from factory. The bolt system on battery isn't the best. GM really need to bolt these down correctly at factory cause average person isn't going to remove the back seat unless theses a reason. This relay fuse issue needs to be recalled and corrected. Maybe they should inform customers to check their battery connections or change the faulty fuse blocks. Many people are spending trying to find a problem. Lots are spending hours online trying to find solutions. There's also reports of blocks burning up again within a year of being replaced.

Yes, That relay is not the best designed seat warmer (joke).

I actually spent weeks trying to get this problem figured out. What it boiled down to was I replaced the fuel pump, fuse block, relay, fuse.

As I probably stated in the original post, I bought this car used from a dealer in Warsaw, Indiana. They really wanted to get rid of it fast because I got an extremely low price. I was kinda prepaired to encounter some issues to get it back in working order. Evidently either the dealer or the last owner got around this problem (?) by installing a 30 amp fuse instead of a 20 amp that it was suppose to have. I am supprised that the test drive actually succeeded when I looked at it.

You might investigate the fuel pump being defective and drawing too much current to run. Otherwise it very well could be the fuse block shorting out. Grab a meter and check the current draw on the relay and then the fuel pump to be sure.

Had I known that the fuse box was built like this I would have ran away from GM and never bought this car. Its the cheapest looking POS that I have ever seen.

All I can say is that I feel your pain. Like me, You think that you buy a "Luxury" car and there would be some quality involved in the design and build. Evidently not.

Since I have replaced all that I have not had an issue since in that area. Car has run ok in respects to that issue.

Contact me if you have questions or want to bounce some questions off me,

coffee

 

[Seth Goldberg]

Re: [SOLVED]Re: 2008 Buick Lucerne Fuel Pump Relay

That's a great theory! Thanks so much for describing this in such detail -- My 2009 Lucerne just hit this exact problem at 61k miles I called the dealership (I was out of warranty) and asked them and they claimed they've never heard of this problem. Like others, I ended up buying a new fuse block from EBay ($70) instead of the ludicrous $280 the dealer wanted. I should get it by mid-next week so I'll post my experience after my mechanic replaces it. I wish I knew this stuff before I had the car towed -- I could have done the repair myself probably and saved a bundle. Oh well.

 

[Seth Goldberg]

Re: [SOLVED]Re: 2008 Buick Lucerne Fuel Pump Relay

What's the part number or recommended replacement relay then? I ordered this one from Amazon:

http://www.amazon.com/gp/product/B007Q1CEUK/

 

[Seth Goldberg]

Hey cardiomac. new here and really would like to know where you found the new box and how you verified it was a "better" one than the one GM put in at the factory. See your PM. Thanks. pyro57

- - - Updated - - -

see your PM's please- pyro57

AFAICT, it's literally the same exact part (verified with the diagram before buying), just way cheaper.

 

[arthur50112]

Has anyone tried replacing the fuse box-block themselves? is the box-block just plug and play, so to speak?
thank you!