As of lately, I have been having an odd issue with my 02 Blazer. The issue is that the fuel pump relay, which has been replaced with a brand new one from the parts store, is showing major signs of heat damage, and also along with that, the car has issues starting and staying running. Sometimes the car shuts off while driving, and afterwards, the car refuses to start up until you pull the relay and re-insert it. We have ran some tests with the relays, using both a jumper cable and the relay itself, and here are the results.

Pin 30 to ground with the engine off gives 12.45 volts.
Pin 30 to ground with the motor running gives 13.70 volts.
Pin 87 to ground gives 13.7 volts as well.
Pin 86 to ground gives 0 volts.

The relay for the fuel pump has been showing heat damage around pins 30 and 87, including burn marks and melting of the relay itself. Keep in mind this is the new relay, not the old one. As well as showing damage, this isn't slow heat build up, it happens quite quickly when the engine is running, making the relay way to hot to touch. We were just wondering if anyone on this forum has had the same issues that we are having, and maybe you have found a solution to the problem. Thanks!

 

I sounds like something in the circuit is pulling to much current, (the pump motor) I am assuming this is fused, if so insure the correct fuse hasn't been replaced with a larger one. Which drops the current on the relay until it acts like the fuse and burns up. My best guess not seeing the circuit is the pump is going bad.

 

I'm not quite clear from your description, did the old relay show the same symptoms also?

 

Ik this I a really late reply but I am having a similar issue as well, except my fuel pump I have to connect or “jump” the fuel pump relay, by adding another relay to it, i was told it was a broken wire somewhere probably in the cpu by the shop that did it, but the weird thing is that it was working just fine not problem until they put the new pump in, any suggestions

 

Do you want to removed the added relay and diagnose what failed in the original circuit and repair it?

How was the extra relay installed, can you draw a diagram?

What is the year and model of your truck?


George

 

I actually went to a pick apart place and pulled a relay box and swapped it hopping for the best and fix both the fuel pump and headlight issues, installed the other box and it started fine and lights worked…. Pretty sure it was just the box goin batty on it