Relay replacement

[turbodaytona87]

Have any of you replaced the old metal style relays with a standard 30amp relay? Did everything work ok? The reason I ask is in taking apart the relays to see which wires go where, I found some diodes inside and wanted to know if they are essential or not. There are two diodes in the cooling fan relay, and one in the starter relay.

[turbovanman²]

As long as they are rated the same and the pinout's match, your good to go.

[turbodaytona87]

They do match, I'm still curious about the reason for the diodes being in there. They're present on the starter relay, and on the cooling fan relay.

[JDAWG]

I don't see it being a problem but something you might want to try out first before you do it on a daily driver. I found it funny there was pics of a car around like last year of a pace car that some guy bought and along the fender were ALL just standard 30a bosch relays, built by chrysler. I got rid of my car but the plan was to get rid of the fusible links in favor of a fuse block and replace all the relays with standard bosch relays. Wiring isnt a problem for me. Maybe the starter relay has to be more heavy duty? Shouldnt be really though cause really all the power comes thru the solenoid ON the starter and you can get around haviing to use a high amperage relay for the rad fan simply by chucking out the stocker that draws a million amps on startup (and while running) for an aftermarket the will draw less amperage and flow more cfm. The ONLY reason why all the plastic relays are different is to make you pay $20 or more for a regular 30a bosch relay which you can pick up lots of 10 on ebay with pigtails for like $15 shipped. Really you could just cut off the tabs on the plugs and on the relays themselves so you can swap them around if you get in trouble somewhere and need to get home.

[83Shelby]

What would I need to do to change over my ASD relay?

[turbovanman²]

What would I need to do to change over my ASD relay?

You'd have to change out the pin locations and I believe its rated alot higher as it runs a few circuits.

[turbodaytona87]

Also on some cars (87- I think?) The ASD relay is in the PM

Thanks guys I'll get it all wired up. I'm almost done except for 2 relays and 3 circuits

[turbodaytona87]

Got everything switched over, it really wasn't too difficult once I got some questions answered. For the record, I did use diodes as in the original configuration. At $4 for 4 of them (only sold in packs of two and I needed three) it was cheap insurance. You can get them from Radioshack. Their part number is 1N4004.

http://starcityracing.com/Forums/showpost.php?p=813936&postcount=172

http://starcityracing.com/Forums/showpost.php?p=814497&postcount=175

http://starcityracing.com/Forums/showpost.php?p=814553&postcount=176

Started the car and everything seems to be working fine. I can't test the A/C clutch turning on the cooling fan since I don't have the A/C charged, but I'm going to assume it works:D

[boydfoose]

There's ton of relay on every vehicle, What would be the difference of Multi Purpose Relay (http://www.thepartsbin.com/brands/omix/omix_multi_purpose_relay.html) to conventional relays coz I'm having a lot of time determining the part that I'll be needing.

[RoadWarrior222]

Diodes are there to prevent back EMF from the coil damaging anything when the relay is deactivated. The magnetic field in the core of a coil induces a current as it collapses.

Edit: YMMV on "Getting away without one" if the new relays have a smaller coil or different core properties (Field doesn't collapse as fast) the drivers in the SMEC/SBEC might survive the smaller pulse... if the pulse is more energetic, you might get instant damage.

[crusty shadow]

^ mostly correct. those bosch 5 pin 30 amp relays which are what i use here at work in remote start installs, and just about everything else for that matter- should have the diodes already built in if you open them up and look.
when i megasquirted my lebaron i replaced all the factory relays with the bosch 30 amp relays, never had a problem with them.