97 Blazer

[ccarmen]

Please help. every time I turn the truck off the #9 fuse blows.
I've replaced the ignition switch and that didn't help.
I can't find the fuel pump relay. i'm not sure if that's doing it.
Thanks.

[mike2004tct]

Originally Posted by ccarmen

Please help. every time I turn the truck off the #9 fuse blows.
I've replaced the ignition switch and that didn't help.
I can't find the fuel pump relay. i'm not sure if that's doing it.
Thanks.

It's behind a cover inside the glove box marked "Relays.
If you swap all three relays and blow a different fuse, you'll know it's a relay.

[ccarmen]

Thanks,
I looked there but the parts store gave me the wrong part then.
because the one in the truck has 5 pins and the part store one has 4 pins.
I will try swaping them.
thanks i'll let you know if it works.

[ccarmen]

Changing the fuses didn't help
any other ideas

thanks

[mike2004tct]

Originally Posted by ccarmen

Changing the fuses didn't help
any other ideas

thanks

I just looked at my fuse cover, #9 is the ECM fuse. What makes you think it's the pump? The key should cut power to everything, including the pump, and the only reason for the pump to pop a fuse would be overcurrent draw during key ON conditions.

I've had both my Ignition switch module and ECM fail within the last 1.5 years, they both have the same symptoms, so here's what you can look for.

Perhaps where your Ignition switch module plugs together under the dash either is A) not making proper contact- the bolt in the center of the connectors, or B) one of the two single row connectors that are part of that connection are in backwards - I sort of doubt this. You might also what to check you connectors at the ECM itself for proper seals, and there's a large connector block on the center of the firewall that hooks into the main harness out of the ECM. This large block connector caused my ECM to toast itself.

[ccarmen]

Thanks Mike

What is the ECM and where is it?

I thought it could be the relay because of the wireing diagram I had.

[mike2004tct]

Originally Posted by ccarmen

Thanks Mike

What is the ECM and where is it?

I thought it could be the relay because of the wireing diagram I had.

ECM or EEM is the Electronic Control Module or as Napa calls it Electronic Engine Module; the brains/computer for your truck. It's mounted on the passenger fender under the hood. It's a black rectangular thing on a heatsink with two large connectors on it.

[rlith]

Could be the ignition switch shorting it out...It's been known to blow both the ECM as well as the TCCM fuse.

[ccarmen]

I've replaced the ignition switch. that didn't help.

[ccarmen]

Is the ECM hard to replace. would I need to do anything special or need special tools?
Thank

[rlith]

Originally Posted by ccarmen

Is the ECM hard to replace. would I need to do anything special or need special tools?
Thank

I doubt very much the ECM is blowing the fuse. You most likely have a wire shorted somewhere and will have to meter all your wiring. If you want to replace the ECM all you need to do is use a 10mm socket to remove the 3 screws holding it to the coolant recovery bottle and then unplug the wires. But again, I would look more towards a wire short. And when you get the new ECM you will have to have it programmed for your VIN #

[ccarmen]

Can a part store program it or a dealer?
Will it need to be in the truck to be programmed?

Metering all the wires sound like more than I will be able to handle.

I’m not sure what I’m going to do now.

Thanks

[rlith]

Originally Posted by ccarmen

Can a part store program it or a dealer?
Will it need to be in the truck to be programmed?

Metering all the wires sound like more than I will be able to handle.

I’m not sure what I’m going to do now.

Thanks

No, the dealership needs to program it with a tech II. Why don't you just have the dealership do the actual diagnosis and you do the rest of the work? th hour or so you pay them to diag where the fault lies would be worth more than just throwing parts at it that may or may not work. It's also cheaper than your agrivation. They have a machine which they can jack straight into your harness at the firewall and the engine harness that can pin point breaks or shorts and tell you where the problem lies.

[mike2004tct]

Napa programmed my rebuilt unit for $125.00. Paid $200 for the unit. 3 hours labor @60.00/hour for diagnostics and replacement. A little over $500.00.

It took my mechanic 2 hours to find the problem. (I'd never go to a Dealer with this, because they charge $100.00/hour in this area)

[ccarmen]

Thanks Rick

I thought that's what I would need to do. But I wanted to ask any way.

Carmen