Rod, as cheap (relatively) as these 53B relays are, and considering that you'll want to disconnect the battery while replacing them, it seems like replacing all the suspect relays (FP, LH, EZK, etc.) at once would be a prudent approach. So what if you don't know which one fixed it? This is one case in which, in my NSH opinion, the shotgun approach is justified.

 

Bob, why would one want to disconnect the battery while replacing relays?

I dont see a need or logic to this.

 

So when you pull the metal cap off trying to unplug them, you won't short anything

(The LH relay in particular has a direct 12v battery connection on the "30" terminal).

 

Jim, You still wont even if you pull the cover off.

When diagnosing problems I actually pull the covers off on purpose and then grab onto the large metal bar with a pair of needle nose pliers. If you touch the windings with the pliers to the large metal bar you will activate the relay though.

 

Worn ignition switch is a possibility.

 

I had an intermttent relay issue. With the CE panel removed and the car running any slight movement or pressure on one of the 53B relays (sorry don't remember which one) caused and arc and instantaneously killed the engine.

The inner connections were bad on the relay causing it to short when moved in the slightest. Doc Brown was surprised to see this. For this reason I will disconnect the battery everytime I replace any relay.

 

I would start with the high current relays first (fuel pump and LH relays). These should be replaced with 40A rated relays.

With fuel and ignition electrical power supplies, only the 'LH' and 'fuel pump' relays handle the high currents that cause relay contact pitting and can cause intermittant type failures.

So, its less likely that 'EZK' or 'Alarm Controller' relays will cause problems.

 

My double-top-secret method for removing relays intact is based on another lisetr's method, using a couple re-formed paint can lid poppers. There's a metal end that goes under the relay on each side, and a risk that the metal will connect something that probably shouldn't be connected. To minimize the need to hide smoke damage and to keep my cheap vinyl electrical tape bill within reason, I just lift the battery ground. Takes a few minutes, saves a lot of potential crying later.

Wally makes a good point about a possible ignition switch issue.


At some point when I have a little time, I'll put together a little diagram of a "telltale" relay that one can use to help find intermittent switches/relays/connections. A relay, an LED, a pushbutton, a diode and a resistor work together to make this amazing diagnostic tool.