This is caused by a running change in 2007/2008 model year. The same fuse box is used for every truck of that rpo but they added a fuel flow control module to better dial in pressure and extend pump life. The module is located above the spare tire and takes over for the relay. Instead of retooling, the harness is blunt cut for the relay at the pump end of the harness and relay left in place. Not a mistake, just cost saving not having multiple parts for the cars
Are you sure that 07-08 Escalades and Denalis Have that above the spare tire? Because the 4.8/5.3’s and maybe the 6.0 Had that especially if it has E85 capability. The Escalades and Denalis didn’t get the E85 option until 09 and I believe then they got that module. I know for sure the fuel pumps are completely different in 07-08 on the Escalades and Denali’s
Also these trucks will run with no power to the fuel pump, because they only have one line that goes to the engine not only will the truck start and run on fumes but the flow of fuel will still happen by the laws of physics. You might not be able to go uphill easily but you can drive straight and downhill no problem. Ask me how I know. Also the STFT’s and the LTFT’s will be demanding more fuel highest numbers I’ve ever seen.
Another example of why GM continues to piss me off. Its no wonder the relay doesn't show up in the wiring diagram. I've been chasing my tail on this one.
Thanks for this, my Escalade cranks but won’t start. Battery and starter are good. So I started switching fuel relay with other relays to see if that’s the problem, come to find out it does nothing?!?! 🤦🏻♂️
@@mercedesbenzs600bash thanks for the suggestion. I actually found the problem, it was a ground wire behind the power steering pump. At first glance it looks like there’s only one 10/12 gauge wire going to that spot, but there’s actually another set of wires that cause a no spark when disconnected off the engine block. All is well now.
@@carlomendoza8588 OK cool,I'm thinking about getting one but it seems like there's some malfunctions but they don't really seem to be major problems...
@Carlo Mendoza is the only ground that you know of doing this? My motor spun a bearing so swapped a used motor in and now it just cranks and won’t start.
@@samlewis19 mine was pretty easy to figure out, because my NO start happen after I changed out motor mounts and exhaust manifold. Once I verified there was fuel pressure going to the fuel rail and MAF sensor to be good I knew it was a spark issue. So that ground wire I mentioned most likely snapped/broke when I had to jack up the engine a little bit to get the old motor mounts out and put new ones in.
My question is why did they make this model without showing which relay pin goes where. I swear every relay in my escalade goes in every which way.... And I always have electrical problems all over my ride. Just want to know which way they all go.
