As the title states i am looking to replace the RAP relay but have yet to find it, any help in locating it is helpful to say the least. I am trying to replace the RAP relay becuase I have been having issues with the dome light shutting off in the cabin and also the radio will get the power completely shut off to it after 5-10min. I have tried the wiper/radio test diagnostic that i have seen in other posts which leads me to replacing the RAP Relay. I have checked underneath the steering column didnt see anything, also checked the driver side kick panel nothing either. I did see some in the glove box 3 to be exact but they are not labeled so i didn't know it to be wise to just start pulling relays.

 

Are there any aftermarket accessories installed on the vehicle? ie. security system, remote start, keyless entry, aftermarket radio, etc.

There is no mention of RAP in the 1997 owners manual, or in the electrical schematic. RAP is controlled by the BCM, and if memory serves correct, 1998 was the first year that had a BCM, (Someone please correct me if I'm wrong). Might be why you can't find the relay on your 1997

 

No BCM in a 97

 

Those relays in the glove box are for fuel pump, horn and power windows.
Check a wiring diagram for your issues.

 

ok got it no RAP Relay, well i have no idea where to start with the wiring TBH. Yes it does have an aftermarket radio and a Viper alarm system but the Blazer has been doing this prior to us having installed the radio/alarm. I did find one thing wrong the wiper motor power plug has a loose socket or a loose wire on the end that goes into the wiper motor(or maybe the socket on the wiper motor is bad?) becuase the wipers wont turn on when you start the car but if you wiggle the power cord just a hair it turns on will will run the duration of the car running, but once the car is turned off it needs to be wiggled again. Oh and the oil gauge while at idle goes so low that the check gauges light comes on but some you press the gas the gauge goes up to the middle mark. Mind you we did replace the oil pump and still does it.

Could just all of these things be piled up into a grounding issue somewhere?

 

Its a known issue with the wiper control pulse board to have bad solder joints.
There is a how to on this site for that issue. You have to remove the board and re solder a few of the contacts.

 

awesome i will fix the wipers on my day off thanks a bunch. What about the Oil gauge i was reading somewhere it is common for the gauges to go bad in the blazer is that true? Also where should i start with the radio issue with it turning off every 10-15min.? The only way to reboot the radio back up is taking it back out of the dash and removing the plug from the back for 30sec.-1min.

 

As for the oil pressure issue... best to rent/borrow/buy an oil pressure tester from the auto parts store. Remove the oil pressure sending unit and install the tester in its place. With the engine at operating temperature, check oil pressure at idle and at 2K rpm, then post the results here.

If the pressure still drops to zero at idle with the tester installed, there might be a weak or broken spring in the oil pump bypass valve, (pressure regulating valve) or the valve is stuck open. It is serviced/replaced without removing the oil pan. The oil filter adapter and oil cooler line fitting must be removed to access the bypass valve. The valve and necessary gasket set cost is under $20. The purpose of the bypass valve is to limit the oil pressure. If it's allowed to get too high, (valve stuck shut) the oil filter will instantly blow apart, (big mess). If the valve stays open, opens too soon, or does not seal, the oil will bypass back into the oil pan all the time, and the oil pressure will be low. The image below is "typical", not exactly like this on the 4.3L, but the end result is the same:



The symptoms you're describing are classic for a faulty bypass valve.

EDIT:
As for the electrical stuff, The ignition switch in your vehicle was only used in 1997, and is known to have a high failure rate. Might be worth looking in to, this thread will help: https://blazerforum.com/forum/articl...-switch-33465/

 

Well at that price point i will just replace the bypass valve(i have already replaced the sending unit thinking it might have been that). Awesome thanks so much for your help Cpt. Hook, what gasket would i need to purchase/bypass valve(all i could find at O'reillys was a Oil Filter Bypass Valve)?(looking to get one at my local O'reillys) Also i just had done the oil pump and replaced my oil will it be leaking oil meaning will i have to do another oil change?

 

When you remove the oil cooler line adapter and oil filter adapter, you'll have a quart or less of oil that drains out. No need to change it again, just top it off when you're done doing the valve.

Here's the gasket set: Felpro Oil Cooler Mounting Set ES 70016: Choose the best Oil Cooler Gasket Set at Advance Auto Parts

As for the valve, in the dealer issue GM factory shop manual, they call it an "oil filter bypass valve". Best to get it at a GM dealer, pretty sure it's under $10.