Main Relay Q:

[95gsrturbo]

My NSX has been garaged for a while because i havent had time to work on it, today i got out and pulled the main relay as i found in another thread.

I read you can repair it by re-soldering the joints. However, they don't seem bad to me. I dont see any cracks in the circuit board, or any bad solder points.

here are a few pics to help

Symptoms were the car would turn over but not start. wants to crank and no battery drainage. The Batt is BRAND NEW. the battery has only started the car one time and i drove 2 miles to the dry cleaners, as i pulled in the car turned off on its own. (hard to say its an ignition switch for this??)

anyhow- ended up pushing it into a parking spot and thats it..... towed it home. tried many times and still nothing.

please advise... for now i think im just gonna order a new Main relay.

 

[Acura NsX Pilot]

From what I remember the cracks are hair line cracks and hard to see but I would just buy another one and try it to see if that solves your problem then you can decide to try and fix your relay from there but if not then you got other problems. The biggest problem is the car not running right now

 

[ftuhy]

If the replacement main relay solves your problem, then its worth a shot at re-flowing the solder on the old relay. That way you'll have a spare.

But as 95gsrturbo noted, the usual problem involves hairline cracks, not easily visible with the naked eye. I usually use a 10x eye loupe to find cracked solder joints.

 

[slamstrom]

You can try to re-solder all the joints, but you will need to de-solder all the joints first. I recently had a main relay issue with my Accord, and I thought about re-soldering the joints (known long term issue for Mistsuba main relay on Accords). I looked at the price for a new relay, and said it is not worth my time to re-solder all the joints; especially when I am a lousy solderer. The relay is about $70 and 1 hour of DIY, issue resolved, and Accord running fine since replacement of main relay. I think the relay for the NSX is about $70 also.

 

[robbiedawg]

you can try to re-solder all the joints, but you will need to de-solder all the joints first. I recently had a main relay issue with my accord, and i thought about re-soldering the joints (known long term issue for mistsuba main relay on accords). I looked at the price for a new relay, and said it is not worth my time to re-solder all the joints; especially when i am a lousy solderer. The relay is about $70 and 1 hour of diy, issue resolved, and accord running fine since replacement of main relay. I think the relay for the nsx is about $70 also.

i just got a main relay for $79.cheap peace of mind in my opinion.

 

[pgilliam1]

I resoldered mine without removing the old solder (I did use flux and a bit of new solder) and it worked fine. The only joints I resoldered were the rectangular, large joints. I could see the cracks in those joints with a magnifier but the other joints looked fine. It's an easy DIY.

 

[Nukem]

I resoldered mine without removing the old solder (I did use flux and a bit of new solder) and it worked fine. The only joints I resoldered were the rectangular, large joints. I could see the cracks in those joints with a magnifier but the other joints looked fine. It's an easy DIY.

I was wondering if its just hairline cracks, then why not just remelt the old solder. Flux helps too.

 

[95gsrturbo]

I orderd a new one from Acura today for about $70 I think - pay for it when it arrives.
Hope it works and solves the problem"...... Summer is almost over I wanna drive my car!

 

[nikey22]

what might be worthwhile is to use a small rubber washer when reattaching the main relay (I dont think there is a grounding issue). I have done this for the igniter unit in the engine bay as well. Both of these get LOTS of vibration and probably is the cause of the solder failure in the first place.

Also there are some differences between the drive-by-wire cars and the none-drive-by-wire cars for the main relay -- order the right one.

 

[xory72]

Just speaking from experience and also getting some facts from an actual NSX certified mechanic, this is one part on the NSX that can and will leave you stranded.

I had been driving my car all day long and on the way home (about 45 miles from my house) I stopped a a store to pick up a soda etc. Came out and my car would turn over but not fire. I tried for 2 hours to get it started and had pulled my entire top rear panels off. I even removed the main relay and put it in the freezer at the store and still no go. I had the car towed back home. (not cheap)

I tested the main replay on the bench and sure enough some output relays did not activate. This main relay switches on a lot of things when the ignition is turned on. When you turn your key in the ignition poisiton you should hear a several clicks immediately from the just behind the pass seat. If you do not here the clicks ... then main relay is toast.

I resoldered everything on the rear of the relay and tested it once again on the bench and it all worked. I installed it back in the car, all the clicks were heard when I turned the key and it started right up. I have now been running the same relay for almost a year now and no issues. I've since purchased a second relay that I keep in the glove compartment just for back up.

As the meachnic said ... this is the ONE part that will keep you completely stranded on the NSX.

 

[95gsrturbo]

Wow o wow... Replaced main relay started right up... Boom!

Still have an O2 issue and a idle issue but one problem is solved...

THANKS PRIME!