Testing the ignition module (amplifier)
 

Searching through threads on this forum I could not find much information on how to test these modules other than swap or swap in a known good one. Since I didn't have a known good one to swap in, I tried disconnecting each in turn (not with the engine running!). Disconnecting one had no effect, but removing the other made the car virtually unstartable- it would crank, fire, and immediately die.

Googling for info on this topic wasn't much help either, but I did run across a tester produced by Innova- the Equus 3015. It was discontinued in 2011, but there are a few units here and there available for around $15, which seemed cheap enough to give it a try (I purchased mine through Amazon). The unit appears to be well made, and the documentation is good.

I got it yesterday and fired it up this morning. Here's a pic of the tester hooked up to the module I removed:


https://cimg0.ibsrv.net/gimg/rennlis...9ccb12166d.jpg

This pic shows one LED steadily lit, which is an indication of a failed unit:


https://cimg2.ibsrv.net/gimg/rennlis...64100db5a3.jpg

The documentation is good, but it notes that the test is more conclusive if an external 12V DC 3A power source is used. None of the recommended parts are available from Innova, but there is a jack on the side of the unit for attaching a wall wart supply- I'll have to look through my collection later and see if I have one. I'll report only if the results are different. Hope this is useful.

There's a procedure in the WSM that describes how you can test them in the car.

How do these go bad on their own?.....I know how mine did...:banghead:

Hi John,

There is a test spec'd on pp. 28-63,64, para. 8ff. using an oscilloscope to test the input signal to the final stages, but I haven't found a test for the module itself. My copy of the WSM is missing a page or two (or I just didn't find them), so if there is a separate test for these modules I would really appreciate the page references where they may be found. (And if the wisdom is contained in para 7-2 of this section, I simply didn't understand it. Also possible.)

Solid state components age, and the aging is hastened by temperature. Although MTBF (mean time between failure) on these units seems pretty high based on common RL experience, it still ends in F.

Interesting test. I have just ordered an Equus 3015 from Amazon, and will be following along.

Helpful as well in my other vehicles for the dreaded GM HEI instant death.


Seth K. Pyle

They call for a silicon paste as I recall to be used to transfer heat to the metal of the body to help cool them..... so definitely are vulnerable to heat probably why they are not near the engine and in front of the radiator too.

True, and some RL'ers have reported that this thermal paste acts like glue and caused the module to split apart on removal. I used a brake adjusting tool to pry against the bottom edge and it came out just fine. But I also noted in another thread that too much paste will actually block heat transfer (this can be a problem replacing a PC's CPU as well) so when I replaced it (a little packet was included with the new module) I used a minimal amount, and used my IR thermometer to check temps after a little running time, just to be sure.

They are also subject to Water if you drive in the rain and especially a heavy down pour can create steam from the heat.

If you have never removed the entire mounting plate (not the modules) and cleaned under it, you will be surprised what you will find, also the small Washer bottle on the other side (non-S4 ;)

Good tips!

The test I was referring to is in Vol. 1A page 28-63.

My WSM is the European version so this page may not be in the US version.

If you want a scan of the page then send an email via my website.

Thanks, John! My copy of the WSM does have that page, but I may be too dense to understand it. I read para 7, "Procedures for checking whether there is an ignition triggering signal from the electronic ignition control unit to the ignition control unit:" and paras. 8 and ff. as describing only a way to test to presence of a signal to the ignition control module (as I have referred to it). Maybe para. 7.2 describes how to test the module itself, but I found this section completely incomprehensible. Any illumination would be very much appreciated!

I think it means if you carry out that test it will trigger the module to give a spark out of the module.

It eliminates the ECU from the list of suspects for this specific test.

Got it - thanks again.

This is what happened to one of my Modules. When I pulled the Module away from the backing plate, the Thermal Gel just stuck and destroyed the little connector wires. Not sure if that tan plate should have come up from the metal plate, together with the top and not separate or not. I just replaced both modules with a used set.

Attachment 1198529

Attachment 1198530